include failed missions in mission format

Since we now have to calculate negative INF with the normal INF (in case both happens), mission formatter now also handles failed missions.

EDPlayerJournal/BGS/MissionFailed.cs

@@ -13,6 +13,21 @@ public class MissionFailed : Transaction {
         Failed = failed;
     }
 
+    /// <summary>
+    /// Returns the amount of influence generated by failing this mission. The
+    /// system returns no influence for one INF missions, but sadly also for
+    /// when the influence had no affect at all (i.e. during a war).
+    /// </summary>
+    public long InfluenceAmount {
+        get {
+            if (Mission == null || string.IsNullOrEmpty(Mission.Influence)) {
+                return -1;
+            } else {
+                return Mission.Influence.Length * -1;
+            }
+        }
+    }
+
     public override int CompareTo(Transaction? other) {
         if (other == null || other.GetType() != typeof(MissionFailed)) {
             return -1;