[BUGFIX] Disable removal of installed extensions

This patch removes the deletion possibility for installed extension in
the list view of the extension manager. Furthermore the javascript can
be adopted as the check for installed extensions can be removed as well.

Resolves: #58493
Related: #53459
Releases: 6.2
Change-Id: I713bbb93230108db144044be9184e77f484931c9
Reviewed-on: https://review.typo3.org/29849
Reviewed-by: Anja Leichsenring
Tested-by: Anja Leichsenring
Reviewed-by: Sascha Wilking
Tested-by: Sascha Wilking
Reviewed-by: Nadir S.
Tested-by: Nadir S.
Reviewed-by: Marc Bastian Heinrichs
Tested-by: Marc Bastian Heinrichs