[BUGFIX] Ensure to properly catch any connection exception

When e.g. a corrupt Database Connection is available
(MySQL down) and no connection is established, the Runtime
Exception should be caught as well.

In addition, the $message is more generic to avoid
any additional output for the end-users.

Resolves: #87993
Releases: master, 9.5
Change-Id: I2495426930d3fab841ff1632d778a945e73b521d
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/60421


Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Tobi Kretschmann <tobi@tobishome.de>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Reviewed-by: Tobi Kretschmann <tobi@tobishome.de>