models.file:OriginalFile.get_action - if action is from alternatives,…

… remove "extension mismatch" warning

Fix #56

acacore/models/file.py

@@ -451,19 +451,23 @@ def get_action(
         :return: The matched ``Action`` object, if any, otherwise ``None``.
         """
         action: Action | None = get_identifier(self, file_classes, actions)
+        from_alternative: bool = False
 
         if action and action.alternatives and (new_puid := action.alternatives.get(self.suffixes.lower(), None)):
             puid: str | None = self.puid
             self.puid = new_puid
             if new_action := self.get_action(actions, file_classes):
                 action = new_action
+                from_alternative = True
             else:
                 self.puid = puid
 
         if set_match and action:
             self.signature = action.name
             self.action = action.action
             self.action_data = action.action_data
+            if from_alternative and self.warning:
+                self.warning = [w for w in self.warning if w.lower() != "extension mismatch"]
         elif set_match:
             self.signature = self.signature if self.puid else None
             self.action = None