fix: skip campaigns with skipped planets

Author: dealloc

src/Helldivers-2-Core/Mapping/V1/CampaignMapper.cs

@@ -14,17 +14,25 @@ public class CampaignMapper
     public IEnumerable<Campaign> MapToV1(MappingContext context, List<Planet> planets)
     {
         foreach (var campaign in context.InvariantWarStatus.Campaigns)
-            yield return MapToV1(campaign, planets);
+        {
+            var result = MapToV1(campaign, planets);
+            
+            if (result is not null)
+                yield return result;
+        }
     }
 
     /// <summary>
     /// Maps ArrowHead's <see cref="Models.ArrowHead.Status.Campaign" /> onto V1's.
     /// </summary>
-    private Campaign MapToV1(Models.ArrowHead.Status.Campaign campaign, List<Planet> planets)
+    private Campaign? MapToV1(Models.ArrowHead.Status.Campaign campaign, List<Planet> planets)
     {
-        var planet = planets.First(p => p.Index == campaign.PlanetIndex);
+        var planet = planets.FirstOrDefault(p => p.Index == campaign.PlanetIndex);
         Static.Factions.TryGetValue(campaign.Race, out var currentOwner);
 
+        if (planet is null)
+            return null;
+
         return new Campaign(
             Id: campaign.Id,
             Planet: planet,

src/Helldivers-2-Core/Mapping/V1/PlanetMapper.cs

@@ -50,7 +50,7 @@ public IEnumerable<Planet> MapToV1(MappingContext context)
             .ToList();
 
         var (name, sector, biomeKey, environmentals) = planet;
-        if (string.IsNullOrWhiteSpace(name) || string.IsNullOrWhiteSpace(sector))
+        if (name is null || string.IsNullOrWhiteSpace(sector))
             return null;
 
         Static.Biomes.TryGetValue(biomeKey, out var biome);