[BUGFIX] Ambiguous output of deprecated RTE properties upgrade wizard

Either some deprecated properties were found, but the wizard was unable
to replace them all automatically, in which case the wizard should
report a failure, or no deprecated properties were found or there are
no more deprecated properties left after the update, in which cases the
wizard should report a success.

Resolves: #51364
Release: 6.2
Change-Id: Ifcddd75f8b257de8ca12038550816f158306d8b5
Reviewed-on: https://review.typo3.org/27369
Reviewed-by: Stanislas Rolland
Tested-by: Stanislas Rolland