SQLAlchemy engine configuration is not passed to FAB based UI. Faced this issue when running Airflow with MySQL metadata store with wait_timeout = 120. Webserver is failing with Internal Server Error due to "[MySQL Server has gone away](https://docs.sqlalchemy.org/en/13/faq/connections.html#mysql-server-has-gone-away)" error. Settings like `sql_alchemy_pool_recycle` and  `sql_alchemy_pool_pre_ping` have no impact on FAB internal communication with MySQL.

**Apache Airflow version**: 1.10.12
airflow/settings.py
# co
        # po
        pool_recycle = conf.getint('core', 'SQL_ALCHEMY_POOL_RECYCLE', fallback=1800)
        # Ch
        # Ty
        # of som
        # More i
        # https:
        pool_pre_ping = conf.getboolean('core', 'SQL_ALCHEMY_POOL_PRE_PING', fallback=True)
        log.debug("settings.configure_orm(): Using pool settings. pool_size=%d, max_overflow=%d, "
                  "pool_recycle=%d, pid=%d", pool_size, max_overflow, pool_recycle, os.getpid())
        engine_args['pool_size'] = pool_size
        engine_args['pool_recycle'] = pool_recycle
        engine_args['pool_pre_ping'] = pool_pre_ping
        engine_args['max_overflow'] = max_overflow
    # Allow the user to specify an encoding for their DB otherwise default
    # to utf-8 so jobs & users with non-latin1 characters can still use us.
    engine_args['encoding'] = conf.get('core', 'SQL_ENGINE_ENCODING', fallback='utf-8')
    if conf.has_option('core', 'sql_alchemy_connect_args'):
        connect_args = conf.getimport('core', 'sql_alchemy_connect_args')
    else:
        connect_args = {}
    engine = create_engine(SQL_ALCHEMY_CONN, connect_args=connect_args, **engine_args)
    setup_event_handlers(engine)
    Session = scoped_session(
        sessionmaker(autocommit=False,
                     autoflush=False,
                     bind=engine,
                     expire_on_commit=False))
def dispose_orm():