[TASK] Move Page Title Generation for search out of TSFE

This change removes the internal property "indexedDocTitle"
which is filled by the PageTitleProvider API.

This API is then moved to Indexed Search to use the same logic
to fetch the "real" page title (without site title etc)
when a plugin is registered.

Resolves: #97861
Releases: main
Change-Id: Ide1b8d1b700d9e555e02d4a02af154f05cb54130
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/75036


Tested-by: core-ci <typo3@b13.com>
Tested-by: Oliver Bartsch <bo@cedev.de>
Tested-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Reviewed-by: Oliver Bartsch <bo@cedev.de>
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>