[BUGFIX] Restore new pages behavior in context menu

In prior versions, creating a new page via the context
menu inserted the new page "inside". This however
changed to "after" in v8, leading to misbehavior,
especially for non-admins, as they are usually not
allowed to create pages on pid=0.

This is now fixed by restoring the previous behavior
of inserting pages "inside" instead of "after".

Resolves: #81405
Releases: master, 10.4
Change-Id: I6a941c3e015189a471d0c136c81f1e5698426dbb
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/72093


Tested-by: Jochen <rothjochen@gmail.com>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Markus Klein <markus.klein@typo3.org>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Oliver Bartsch <bo@cedev.de>
Reviewed-by: Jochen <rothjochen@gmail.com>
Reviewed-by: Markus Klein <markus.klein@typo3.org>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Oliver Bartsch <bo@cedev.de>