language selector: increase only picker list view

As that's what matters for the selection, having parts of the already
selected language cut off is not really a big deal as either one
knows the language and the initial native part is enough or the
picker needs to be opened for changing selection anyway.

But, we can give the field itself a bit more space by reducing the
label width to 75, which is enough for all languages as grepping our
PO files for "Language" and their translation, it seems that the
widest one comes from Euskara (Basque) with its "Hizkuntza" having 9
characters.

This way we avoid having to many different

Fixes: 454ff6e ("language selector: increase field width")
Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>