### 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
self,
        instance: str,
        database: str,
        body: Dict,
        project_id: str,
    ) -> None:
        """
        Updates a database resource inside a Cloud SQL instance.
        This method supports patch semantics.
        See https://cloud.google.com/sql/docs/mysql/admin-api/how-tos/performance#patch.
        :param instance: Database instance ID. This does not include the project ID.
        :type instance: str
        :param database: Name of the database to be updated in the instance.
        :type database: str
        :param body: The request body, as described in
            https://cloud.google.com/sql/docs/mysql/admin-api/v1beta4/databases/insert#request-body.
        :type body: dict
        :param project_id: Project ID of the project that contains the instance. If set
            to None or missing, the default project_id from the Google Cloud connection is used.
        :type project_id: str
        :return: None
        """
        response = (
            self.get_conn()
            .databases()