[TASK] Remove superfluous margin above #typo3-menu

Added padding-top to start the first li in the menue at the bottom line
of the first grey space in the content-area

Resolves: #57098
Releases: 6.2
Change-Id: I8ec5defea0cfae9483cfd19bdb918ee063b22f70
Reviewed-on: https://review.typo3.org/28556
Reviewed-by: Anja Leichsenring
Tested-by: Anja Leichsenring
Reviewed-by: Wouter Wolters
Tested-by: Wouter Wolters
Reviewed-by: Christian Kuhn
Tested-by: Christian Kuhn