[BUGFIX] Register page tree navigation component after it is initialized

Now Viewport.NavigationContainer.setComponentInstance(tree);
is called after the tree is initialized.
A check to prevent multiple initialization calls is added.

Also position of the title edit imput is corrected
in case where there are multiple mount points.

Releases: master
Resolves: #83299
Change-Id: I5b9cc14b362ab20ecb7631babe3f3f83eb8bfb48
Reviewed-on: https://review.typo3.org/55043


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Stefan Neufeind <typo3.neufeind@speedpartner.de>
Tested-by: Stefan Neufeind <typo3.neufeind@speedpartner.de>
Reviewed-by: Frans Saris <franssaris@gmail.com>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Frans Saris <franssaris@gmail.com>
Reviewed-by: Tymoteusz Motylewski <t.motylewski@gmail.com>
Tested-by: Tymoteusz Motylewski <t.motylewski@gmail.com>