[TASK] Drop handling for non existent contentNavigationSwitcher

The handling was introduced in [1] to have a resizable navigation area.
With the introduction of a generalized Lit component, the handling was
incompletely removed in [2].

[1] https://review.typo3.org/c/Packages/TYPO3.CMS/+/67511
[2] https://review.typo3.org/c/Packages/TYPO3.CMS/+/68692

Resolves: #100424
Releases: main
Change-Id: I20bb526e2c3e82e407d905209fddf9a36feeae0d
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/78433


Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Benni Mack <benni@typo3.org>
Tested-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>