add warning for empty mission faction

EDPlayerJournal/BGS/TransactionParser.cs

@@ -631,6 +631,14 @@ internal class MissionFailedParser : TransactionParserPart {
             return;
         }
 
+        if (string.IsNullOrEmpty(mission.Faction)) {
+            transactions.AddIncomplete(new MissionFailed(),
+                "Could not determine for what faction you failed a mission. This happens if the " +
+                "mission acceptance is not within the given time frame.",
+                entry
+                );
+        }
+
         transactions.Add(new MissionFailed(entry) {
             Faction = mission?.Faction,
             Mission = mission,