Swap send_mime_email in core to use Connection instead of BaseHook

[amoghrajesh]

Extracted out of: #54083, to fix:

______________________________________________________________________________ TestEmailSmtp.test_send_mime_airflow_config _______________________________________________________________________________
airflow-core/tests/unit/utils/test_email.py:218: in test_send_mime_airflow_config
email.send_mime_email("from", "to", msg, dryrun=False)
airflow-core/src/airflow/utils/email.py:251: in send_mime_email
airflow_conn = BaseHook.get_connection(conn_id)
task-sdk/src/airflow/sdk/bases/hook.py:63: in get_connection
conn = Connection.get(conn_id)
task-sdk/src/airflow/sdk/definitions/connection.py:154: in get
return _get_connection(conn_id)
task-sdk/src/airflow/sdk/execution_time/context.py:153: in _get_connection
from airflow.sdk.execution_time.task_runner import SUPERVISOR_COMMS
E ImportError: cannot import name 'SUPERVISOR_COMMS' from 'airflow.sdk.execution_time.task_runner' (/opt/airflow/task-sdk/src/airflow/sdk/execution_time/task_runner.py)

The core email functionality has no reason to use BaseHook (from sdk). Swapping to use connection models. This will cut the link between sdk and core too.

Extracted out of #54083

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