### Apache Airflow Provider(s)

google

### Versions of Apache Airflow Providers

apache-airflow-providers-google~=5.0

### Apache Airflow version

2.1.3 (latest released)

### Operating System

MacOS Big Sur

### Deployment

Astronomer

### Deployment details

_No response_

### What happened

The CloudSqlProxyRunner queries the Airflow DB directly to retrieve the GCP connection.

https://github.com/apache/airflow/blob/7b3a5f95cd19667a683e92e311f6c29d6a9a6a0b/airflow/providers/google/cloud/hooks/cloud_sql.py#L521

### What you expected to happen

In order to not break when using connections stored in external secrets backends, it should use standardized methods to retrieve connections and not query the Airflow DB directly.

### How to reproduce

Use a CloudSQLDatabaseHook with `use_proxy=True` while using an external secrets backend.

### Anything else

Every time

### Are you willing to submit PR?

- [X] Yes I am willing to submit a PR!

### Code of Conduct

- [X] I agree to follow this project's [Code of Conduct](https://github.com/apache/airflow/blob/main/CODE_OF_CONDUCT.md)

airflow/providers/google/cloud/hooks/cloud_sql.py
"""Helper class with operation statuses."""
    PENDING = "PENDING"
    RUNNING = "RUNNING"
    DONE = "DONE"
    UNKNOWN = "UNKNOWN"
class CloudSQLHook(GoogleBaseHook):
    """
    Hook for Google Cloud SQL APIs.
    All the methods in the hook where project_id is used must be called with
    keyword arguments rather than positional.
    :param api_version: This is the version of the api.
    :type api_version: str
    :param gcp_conn_id: The Airflow connection used for GCP credentials.
    :type gcp_conn_id: str
    :param delegate_to: This performs a task on one host with reference to other hosts.
    :type delegate_to: Optional[str]
    :param impersonation_chain: This is the optional service account to impersonate using short term
        credentials.
    :type impersonation_chain: Optional[str]
    """
    conn_name_attr = 'gcp_conn_id'
    default_conn_name = 'google_cloud_sql_default'
    conn_type = 'gcpcloudsql'
    hook_name = 'Google Cloud SQL'
    def __init__(