[TASK] Remove superfluous parenthesis in sysexts

Removes superfluous parenthesis in sysexts "t3skin", "taskcenter",
"tsconfig_help" and "tstemplate".

Change ("a" . "b") . "c" into "a" . "b" . "c" using the lex-pass tool.

Change-Id: I9034b5146aa02651e99ab3651c50d785423e64c2
Resolves: #40972
Related: #40095
Reviewed-on: http://review.typo3.org/14631
Reviewed-by: Wouter Wolters
Tested-by: Wouter Wolters
Reviewed-by: Jigal van Hemert
Tested-by: Jigal van Hemert