**Apache Airflow version**: 2.1.0


**Kubernetes version (if you are using kubernetes)** (use `kubectl version`): N/A

**Environment**:

- **Cloud provider or hardware configuration**: Astronomer-based local setup using Docker `quay.io/astronomer/ap-airflow:2.1.0-2-buster-onbuild`
- **OS** (e.g. from /etc/os-release): `Debian GNU/Linux 10 (buster)`
- **Kernel** (e.g. `uname -a`): `Linux 7a92d1fd4406 5.10.25-linuxkit #1 SMP Tue Mar 23 09:27:39 UTC 2021 x86_64 GNU/Linux`
- **Install tools**: apache-airflow-providers-snowflake
- **Others**:

**What happened**:

Having configured Snowflake connection and pointing to GCP Secret Manager backend `AIRFLOW__SECRETS__BACKEND=airflow.providers.google.cloud.secrets.secret_manager.CloudSecretManagerBackend` I am getting a pretty consistent error traced all the way down to gRPC

```File "/usr/local/lib/python3.7/site-packages/google/api_core/grpc_helpers.py", line 57, in error_remapped_callable
    return callable_(*args, **kwargs)
  File "/usr/local/lib/python3.7/site-packages/grpc/_channel.py", line 946, in __call__
    return _end_unary_response_blocking(state, call, False, None)
  File "/usr/local/lib/python3.7/site-packages/grpc/_channel.py", line 849, in _end_unary_response_blocking
    raise _InactiveRpcError(state)
grpc._channel._InactiveRpcError: <_InactiveRpcError of RPC that terminated with:
	status = StatusCode.UNKNOWN
	details = "Stream removed"
	debug_error_string = "{"created":"@1624370913.481874500","description":"Error received from peer ipv4:172.xxx.xx.xxx:443","file":"src/core/lib/surface/call.cc","file_line":1067,"grpc_message":"Stream removed","grpc_status":2}"
>

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/usr/local/lib/python3.7/site-packages/airflow/models/taskinstance.py", line 1137, in _run_raw_task
    self._prepare_and_execute_task_with_callbacks(context, task)
  File "/usr/local/lib/python3.7/site-packages/airflow/models/taskinstance.py", line 1311, in _prepare_and_execute_task_with_callbacks
    result = self._execute_task(context, task_copy)
  File "/usr/local/lib/python3.7/site-packages/airflow/models/taskinstance.py", line 1341, in _execute_task
    result = task_copy.execute(context=context)
  File "/usr/local/lib/python3.7/site-packages/airflow/operators/python.py", line 150, in execute
    return_value = self.execute_callable()
  File "/usr/local/lib/python3.7/site-packages/airflow/operators/python.py", line 161, in execute_callable
    return self.python_callable(*self.op_args, **self.op_kwargs)
  File "/usr/local/airflow/dags/qe/weekly.py", line 63, in snfk_hook
    df = hook.get_pandas_df(sql)
  File "/usr/local/lib/python3.7/site-packages/airflow/hooks/dbapi.py", line 116, in get_pandas_df
    with closing(self.get_conn()) as conn:
  File "/usr/local/lib/python3.7/site-packages/airflow/providers/snowflake/hooks/snowflake.py", line 220, in get_conn
    conn_config = self._get_conn_params()
  File "/usr/local/lib/python3.7/site-packages/airflow/providers/snowflake/hooks/snowflake.py", line 152, in _get_conn_params
    self.snowflake_conn_id  # type: ignore[attr-defined] # pylint: disable=no-member
  File "/usr/local/lib/python3.7/site-packages/airflow/hooks/base.py", line 67, in get_connection
    conn = Connection.get_connection_from_secrets(conn_id)
  File "/usr/local/lib/python3.7/site-packages/airflow/models/connection.py", line 376, in get_connection_from_secrets
    conn = secrets_backend.get_connection(conn_id=conn_id)
  File "/usr/local/lib/python3.7/site-packages/airflow/secrets/base_secrets.py", line 64, in get_connection
    conn_uri = self.get_conn_uri(conn_id=conn_id)
  File "/usr/local/lib/python3.7/site-packages/airflow/providers/google/cloud/secrets/secret_manager.py", line 134, in get_conn_uri
    return self._get_secret(self.connections_prefix, conn_id)
  File "/usr/local/lib/python3.7/site-packages/airflow/providers/google/cloud/secrets/secret_manager.py", line 170, in _get_secret
    return self.client.get_secret(secret_id=secret_id, project_id=self.project_id)
  File "/usr/local/lib/python3.7/site-packages/airflow/providers/google/cloud/_internal_client/secret_manager_client.py", line 86, in get_secret
    response = self.client.access_secret_version(name)
  File "/usr/local/lib/python3.7/site-packages/google/cloud/secretmanager_v1/gapic/secret_manager_service_client.py", line 968, in access_secret_version
    request, retry=retry, timeout=timeout, metadata=metadata
  File "/usr/local/lib/python3.7/site-packages/google/api_core/gapic_v1/method.py", line 145, in __call__
    return wrapped_func(*args, **kwargs)
  File "/usr/local/lib/python3.7/site-packages/google/api_core/retry.py", line 286, in retry_wrapped_func
    on_error=on_error,
  File "/usr/local/lib/python3.7/site-packages/google/api_core/retry.py", line 184, in retry_target
    return target()
  File "/usr/local/lib/python3.7/site-packages/google/api_core/timeout.py", line 214, in func_with_timeout
    return func(*args, **kwargs)
  File "/usr/local/lib/python3.7/site-packages/google/api_core/grpc_helpers.py", line 59, in error_remapped_callable
    six.raise_from(exceptions.from_grpc_error(exc), exc)
  File "<string>", line 3, in raise_from
google.api_core.exceptions.Unknown: None Stream removed
```

**What you expected to happen**:

DAG successfully retrieves a configured connection for Snowflake from GCP Secret Manager and executes a query returning back a result.

**How to reproduce it**:
1. Configure Google Cloud Platform as secrets backend
`AIRFLOW__SECRETS__BACKEND=airflow.providers.google.cloud.secrets.secret_manager.CloudSecretManagerBackend`
2. Configure a Snowflake connection (`requirements.txt` has `apache-airflow-providers-snowflake`)
3. Create a DAG which uses SnowflakeHook similar to this:

```python
import logging

import airflow
from airflow import DAG
from airflow.operators.python_operator import PythonOperator
from airflow.contrib.hooks.snowflake_hook import SnowflakeHook
from airflow.contrib.operators.snowflake_operator import SnowflakeOperator

logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)

args = {"owner": "Airflow", "start_date": airflow.utils.dates.days_ago(2)}

dag = DAG(
    dag_id="snowflake_automation", default_args=args, schedule_interval=None
)

snowflake_query = [
    """create table public.test_employee (id number, name string);""",
    """insert into public.test_employee values(1, “Sam”),(2, “Andy”),(3, “Gill”);""",
]


def get_row_count(**context):
    dwh_hook = SnowflakeHook(snowflake_conn_id="snowflake_conn")
    result = dwh_hook.get_first("select count(*) from public.test_employee")
    logging.info("Number of rows in `public.test_employee`  - %s", result[0])

with dag:
    create_insert = SnowflakeOperator(
        task_id="snowfalke_create",
        sql=snowflake_query ,
        snowflake_conn_id="snowflake_conn",
    )

    get_count = PythonOperator(task_id="get_count", python_callable=get_row_count)

create_insert >> get_count
```

**Anything else we need to know**:

I looked around to see if this is an issue with Google's `api-core` and it seems like somebody has done research into it to point out that it might be downstream implementation issue and not the `api-core` issue: https://stackoverflow.com/questions/67374613/why-does-accessing-this-variable-fail-after-it-is-used-in-a-thread

airflow/providers/google/cloud/secrets/secret_manager.py
"""
        Get Airflow Variable from Environment Variable
        :param key: Variable Key
        :return: Variable Value
        """
        if self.variables_prefix is None:
            return None
        return self._get_secret(self.variables_prefix, key)
    def get_config(self, key: str) -> Optional[str]:
        """
        Get Airflow Configuration
        :param key: Configuration Option Key
        :return: Configuration Option Value
        """
        if self.config_prefix is None:
            return None
        return self._get_secret(self.config_prefix, key)
    def _get_secret(self, path_prefix: str, secret_id: str) -> Optional[str]:
        """
        Get secret value from the SecretManager based on prefix.
        :param path_prefix: Prefix for the Path to get Secret
        :type path_prefix: str
        :param secret_id: Secret Key
        :type secret_id: str
        """
        secret_id = self.build_path(path_prefix, secret_id, self.sep)
        return self.client.get_secret(secret_id=secret_id, project_id=self.project_id)