[TASK] Improve doc header for smaller screens

To make the doc header nicer on smaller (13") screens, the following
changes are applied:

- Remove the label of the language select box
- Remove the media query

Resolves: #79701
Releases: master
Change-Id: Ie3581c37f4169c89aa72aa3a429dbdf073901e0f
Reviewed-on: https://review.typo3.org/51602


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Josef Glatz <josef.glatz@typo3.org>
Tested-by: Josef Glatz <josef.glatz@typo3.org>
Tested-by: Riccardo De Contardi <erredeco@gmail.com>
Reviewed-by: Benni Mack <benni@typo3.org>
Tested-by: Benni Mack <benni@typo3.org>