[BUGFIX] Fix keyboard behaviour on pagetree root node

- Do not toggle node with canToggle!==true
- Check if node has parent before trying to go to parent node

Resolves: #89847
Resolves: #89864
Releases: master
Change-Id: I49f112c15e64103e707481cecb7f61bd58fa8182
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/62544


Tested-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Susanne Moog <look@susi.dev>
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Reviewed-by: Susanne Moog <look@susi.dev>