Fix message_pin, message_unpin target id being None

Co-authored-by: Michael H <[email protected]>
Co-authored-by: Alex Nørgaard <[email protected]>

discord/audit_logs.py

@@ -874,7 +874,13 @@ class AuditLogEntry(Hashable):
     def _convert_target_emoji(self, target_id: int) -> Union[Emoji, Object]:
         return self._state.get_emoji(target_id) or Object(id=target_id, type=Emoji)
 
-    def _convert_target_message(self, target_id: int) -> Union[Member, User, Object]:
+    def _convert_target_message(self, target_id: Optional[int]) -> Optional[Union[Member, User, Object]]:
+        # The message_pin and message_unpin action types do not have a
+        # non-null target_id so safeguard against that
+
+        if target_id is None:
+            return None
+
         return self._get_member(target_id) or Object(id=target_id, type=Member)
 
     def _convert_target_stage_instance(self, target_id: int) -> Union[StageInstance, Object]: