[FOLLOWUP][BUGFIX] Hide language switcher if record has no default translation

In the current implementation it is not possible to create a new translations outside
of the default translation. So we can readd the new translation option when the record
has a default translation.

Change-Id: I89c4200ff847dadfdeec03b5f43a6577f40702e3
Resolves: #72797
Releases: master, 7.6
Reviewed-on: https://review.typo3.org/51092


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Reviewed-by: Andreas Fernandez <typo3@scripting-base.de>
Tested-by: Mona Muzaffar <mona.muzaffar@gmx.de>
Reviewed-by: Josef Glatz <josef.glatz@typo3.org>
Tested-by: Josef Glatz <josef.glatz@typo3.org>
Reviewed-by: Alexander Opitz <opitz.alexander@googlemail.com>
Tested-by: Alexander Opitz <opitz.alexander@googlemail.com>