[BUGFIX] Fix page.headerData + USER_INT

INT scripts placed in page.headerData.XX were
not replaced any more after introducing USER_INT
capabilities of the pageRenderer in #22273

This change reprocesses _INT placeholders after
the pageRenderer replacements have been done.

Resolves: #44825
Releases: 6.0, 6.1, 6.2
Change-Id: If11b692ed75120dbf122d95ca497b5e382fdf349
Reviewed-on: https://review.typo3.org/23982
Reviewed-by: Helmut Hummel
Tested-by: Helmut Hummel