This commit adds a check to prevent saving a translation in a language that was not installed.
Upon adding a translation, the field "language" in the request was not checker,
allowing to add translation for language (or any strings as key) for a given field
This is not ideal and we want to prevent that, it can bloat the database for no reason.
opw-3208305
closesodoo/odoo#114793
X-original-commit: 89cd5ce88a0c666e811410e264e3cb474f9851c0
Signed-off-by: Vranckx Florian (flvr) <flvr@odoo.com>