[BUGFIX] Update description on changed error reporting defaults

In #35154 the PHP error_reporting defaults have changed and
this now changes the description in the install tool.

Change-Id: I5c5b0fec5f7e521fcd61812a36149590e08905fa
Fixes: #38240
Releases: 6.0, 4.7, 4.6, 4.5
Reviewed-on: https://review.typo3.org/17625
Reviewed-by: Mattias Nilsson
Reviewed-by: Christian Kuhn
Tested-by: Christian Kuhn