[BUGFIX] Fix template rootline for translated pages

The TypoScript template rootline in the Frontend will not be
changed any more if a different sys_language_uid is used.

The data of the current rootLine will be overwritten with the
translated rootLine data.

Resolves: #48300
Releases: 6.2, 6.1
Change-Id: I38bd4a6f3d3c2f15712003b1d1a1334284ebe9b0
Reviewed-on: https://review.typo3.org/21449
Reviewed-by: Wouter Wolters
Tested-by: Wouter Wolters