[BUGFIX] Preserve selection ranges in RteLinkBrowser

When the RteLinkBrowser is opened, any active ranges are now backed up
and reused later when an element gets linked. This fixes clashes with
the browser's internal search feature that overrides the `Selection`
object.

Resolves: #90952
Releases: master, 9.5
Change-Id: I155157e808370cd5ff05076a6c82f09da3b0cb3c
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/64078


Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Josef Glatz <josefglatz@gmail.com>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Reviewed-by: Josef Glatz <josefglatz@gmail.com>