Add null check for tournament in match formatting

tournaments/models/match.py

@@ -479,7 +479,8 @@ class Match(TournamentSubModel):
 
         ended = self.end_date is not None
         live_format = "Format "
-        if self.get_tournament().day_duration >= 7:
+        tournament = self.get_tournament()
+        if tournament and tournament.day_duration >= 7:
             live_format = ""
         live_format = live_format + FederalMatchCategory(self.format).format_label_short