Electric no longer performs automatic fallback to disabling SSL for database connections

[alco]

Prior to #1762, Electric tried to connect to the database using SSL first, then fall back to using an unencrypted connection unless the DATABASE_URL config had the sslmode query parameter in it.

#1762 made changes to the DB connection setup and, as an accidental side effect, Electric no longer performs the automatic fallback. I believe this wouldn't have happened if the fallback logic hadn't been moved from ConnectionManager to ReplicationClient in #1594.

To fix this regression, we need to move the fallback logic back to ConnectionManager and add an integration test to preclude future regressions.

[balegas]

• let's not forget to revert in Update docker-compose.yaml #1781 (comment)