Improved Database Connector Connection Experience

[bleonard]

Collecting issues where w could have better handled a connection or permission problem.
The better experience is closer to a failed check that directs the user to fix their details.
It's interesting that these can happen in the middle of a sync due to network (or related) issues. In the ideal case, we would end more gracefully - save the progress and pick it back up next time.

Let's be sure we fully understand this related change: #16202
And then then make sure we update that approach as needed to;

• have better error messages
• make it so a connection can experience config problems in the middle of a sync and we stop processing as gracefully as possible.
• not affect sentry in connection (including ssh) issues (in and command: check, discover, sync)