### Apache Airflow version

main (development)

### What happened

1. When not providing `project_id` to `BigQueryGetDataOperator` in deferrable mode (`project_id=None`), the query generated by `generate_query` method is bugged, i.e.,: 

````sql
from `None.DATASET.TABLE_ID` limit ...
````

2. `as_dict` param does not work `BigQueryGetDataOperator`.

### What you think should happen instead

1. When `project_id` is `None` - it should be removed from the query along with the trailing dot, i.e.,:

````sql
from `DATASET.TABLE_ID` limit ...
````

2. `as_dict` should be added to the serialization method of `BigQueryGetDataTrigger`.

### How to reproduce

1. Create a DAG file with `BigQueryGetDataOperator` defined as follows:
```python
BigQueryGetDataOperator(
        task_id="bq_get_data_op",
        # project_id="PROJECT_ID",  <-- Not provided
        dataset_id="DATASET",
        table_id="TABLE",
        use_legacy_sql=False,
        deferrable=True
    )
````

2. 1. Create a DAG file with `BigQueryGetDataOperator` defined as follows:
```python
BigQueryGetDataOperator(
        task_id="bq_get_data_op",
        project_id="PROJECT_ID",
        dataset_id="DATASET",
        table_id="TABLE",
        use_legacy_sql=False,
        deferrable=True,
        as_dict=True
    )
````

### Operating System

Debian

### Versions of Apache Airflow Providers

_No response_

### Deployment

Official Apache Airflow Helm Chart

### Deployment details

_No response_

### Anything else

The `generate_query` method is not unit tested (which would have prevented it in the first place) - will be better to add one.

### 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)

@mock.patch("airflow.providers.google.cloud.operators.bigquery.BigQueryHook")
    def test_execute(self, mock_hook):
        operator = BigQueryGetDatasetTablesOperator(
            task_id=TASK_ID, dataset_id=TEST_DATASET, project_id=TEST_GCP_PROJECT_ID, max_results=2
        )
        operator.execute(None)
        mock_hook.return_value.get_dataset_tables.assert_called_once_with(
            dataset_id=TEST_DATASET,
            project_id=TEST_GCP_PROJECT_ID,
            max_results=2,
        )
@pytest.mark.parametrize(
    "operator_class, kwargs",
    [
        (BigQueryCheckOperator, dict(sql="Select * from test_table")),
        (BigQueryValueCheckOperator, dict(sql="Select * from test_table", pass_value=95)),
        (BigQueryIntervalCheckOperator, dict(table=TEST_TABLE_ID, metrics_thresholds={"COUNT(*)": 1.5})),
    ],
)
class TestBigQueryCheckOperators: