Catch `ValueError` when initialising `SQLTrackerStore` and re-raise as `RasaException`

[sentry-io]

Sentry Issue: RASA-OPEN-SOURCE-FR1

ValueError: invalid literal for int() with base 10: '$DB_PORT'
(12 additional frame(s) were not displayed)
...
  File "rasa/core/run.py", line 255, in load_agent_on_start
    _tracker_store = TrackerStore.create(endpoints.tracker_store, event_broker=_broker)
  File "rasa/core/tracker_store.py", line 124, in create
    return _create_from_endpoint_config(obj, domain, event_broker)
  File "rasa/core/tracker_store.py", line 1269, in _create_from_endpoint_config
    **endpoint_config.kwargs,
  File "rasa/core/tracker_store.py", line 860, in __init__
    dialect, host, port, db, username, password, login_db, query
  File "rasa/core/tracker_store.py", line 953, in get_db_url
    query=query,

Definition of Done:

• implement try/except block for casting port to integer, otherwise raise RasaException

[ancalita]

Closed via #10750