[TASK] Improve accessibility in ClearCacheToolbar dropdown

To improve accessibility in ClearCacheToolbar dropdown menu, the
descriptive text of each entry is hidden for screen readers and
re-inserted after the link.

Resolves: #104086
Releases: main, 12.4
Change-Id: I30f862cb420cb01f837014872174967c1041df2e
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/85531


Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: core-ci <typo3@b13.com>