[FIX] tools: Avoid to delete translation for Structured Model fields

Issue: Translation missing after upgrade when the customer had any
       other language except English and he changed the value instead
       of translation.

In this commit, avoid to delete the translation.

closes odoo/odoo#135760

Opw: 3489453
Signed-off-by: Raphael Collet <rco@odoo.com>

odoo/tools/translate.py

@@ -1589,6 +1589,8 @@ def _get_translation_upgrade_queries(cr, field):
 
     # upgrade model_terms translation: one update per field per record
     if callable(field.translate):
+        cr.execute("SELECT code FROM res_lang WHERE active = 't'")
+        languages = {l[0] for l in cr.fetchall()}
         query = f"""
             SELECT t.res_id, m."{field.name}", t.value, t.noupdate
               FROM t
@@ -1642,6 +1644,12 @@ def _get_translation_upgrade_queries(cr, field):
                 new_values["en_US"] = field.translate(lambda v: None, src_value)
             if extra and extra[0] not in new_values:
                 new_values[extra[0]] = new_values["en_US"]
+            elif not extra:
+                missing_languages = languages - set(translations)
+                if missing_languages:
+                    src_value = field.translate(lambda v: None, src_value)
+                    for lang in sorted(missing_languages):
+                        new_values[lang] = src_value
             query = f'UPDATE "{Model._table}" SET "{field.name}" = %s WHERE id = %s'
             migrate_queries.append(cr.mogrify(query, [Json(new_values), id_]).decode())