[BUGFIX] Unify MetaTagApi removal methods

Add strtolower calls at `GenericMetaTagManager::removeProperty` to be in
sync with `PageRenderer::removeMetaTag`.

Resolves: #100198
Releases: main, 11.5
Change-Id: If758375d3293cbcd8897891a866c6cf6fb6df508
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/78064


Tested-by: Georg Ringer <georg.ringer@gmail.com>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: core-ci <typo3@b13.com>