[BUGFIX] Fix some typos and improve PHPDoc comments

Fixes several typos and improves readability of PHPDoc
comments through ext:dashboard classes.

Resolves: #90486
Releases: master
Change-Id: I27cd1c0c2dd3c3b18bade0b50af41aa8d8bfd06e
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/63368


Tested-by: Richard Haeser <richard@maxserv.com>
Tested-by: Susanne Moog <look@susi.dev>
Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Daniel Goerz <daniel.goerz@posteo.de>
Reviewed-by: Richard Haeser <richard@maxserv.com>
Reviewed-by: Susanne Moog <look@susi.dev>
Reviewed-by: Daniel Goerz <daniel.goerz@posteo.de>