### 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
import os
import os.path
import platform
import random
import re
import shutil
import socket
import string
import subprocess
import time
import uuid
from pathlib import Path
from subprocess import PIPE, Popen
from typing import Any, Dict, List, Optional, Sequence, Union
from urllib.parse import quote_plus
import httpx
from googleapiclient.discovery import Resource, build
from googleapiclient.errors import HttpError
from sqlalchemy.orm import Session
from airflow.exceptions import AirflowException
from airflow.hooks.base import BaseHook
from airflow.models import Connection
from airflow.providers.google.common.hooks.base_google import GoogleBaseHook
from airflow.providers.mysql.hooks.mysql import MySqlHook
from airflow.providers.postgres.hooks.postgres import PostgresHook
from airflow.utils.log.logging_mixin import LoggingMixin
from airflow.utils.session import provide_session
UNIX_PATH_MAX = 108
TIME_TO_SLEEP_IN_SECONDS = 20
class CloudSqlOperationStatus: