[CLEANUP] Avoid double parsing of includes

The Template Analyzer BE module parses TypoScript for
included files twice.

Resolves: #50473
Releases: 6.2
Change-Id: I5794b55d22e3ca139112477cd28c5ad4477e97cc
Reviewed-on: https://review.typo3.org/22612
Reviewed-by: Wouter Wolters
Tested-by: Wouter Wolters
Reviewed-by: Christian Kuhn
Tested-by: Christian Kuhn