[BUGFIX] Set default controller name in ExtbasePluginEnhancer

The `defaultController` setting is only applied if both `action` and
`controller` parameters are empty. In Extbase context it happens that
only `action` is defined, but `controller` is empty (since linking to
the very same controller, just changing the action).

The behavior now is the following:
* set `action` and `controller` parameters to default if not given
* set `controller` parameter to default if not given

Resolves: #87337
Releases: master, 9.5
Change-Id: I3ee730f6bc665808c59cc07907467aa98c2de21a
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/59659


Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Susanne Moog <look@susi.dev>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Jörg Bösche <typo3@joergboesche.de>
Reviewed-by: Benni Mack <benni@typo3.org>
Reviewed-by: Susanne Moog <look@susi.dev>