[BUGFIX] Prefix single digit dates with 0 instead of whitespace

The backend query view, used for csv exports and lists, uses a date
format where single digit days of a date value are prefixed with a
whitespace instead of a 0.
This ends up in useless CSV exports that can not be interpreted by
tools like Excel.

Change-Id: Ie11c5f8a923eb412f014f06df528a2aa0101a0d4
Resolves: #81551
Releases: master,8.7
Reviewed-on: https://review.typo3.org/53191


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Benni Mack <benni@typo3.org>
Tested-by: Benni Mack <benni@typo3.org>