fix bugs with viewing movies as they are loading

ErsatzTV.Core/Scheduling/PlayoutBuilder.cs

@@ -408,7 +408,8 @@ namespace ErsatzTV.Core.Scheduling
                 {
                     CollectionType = item.CollectionType,
                     Id = item.TelevisionSeasonId.Value
-                }
+                },
+                _ => throw new ArgumentOutOfRangeException(nameof(item))
             };
 
         private class CollectionKey : Record<CollectionKey>

ErsatzTV/Pages/MovieList.razor

@@ -20,7 +20,7 @@
 </MudContainer>
 
 <MudContainer MaxWidth="MaxWidth.False" Class="media-card-grid">
-    @foreach (MovieCardViewModel card in _data.Cards)
+    @foreach (MovieCardViewModel card in _data.Cards.Where(d => !string.IsNullOrWhiteSpace(d.Title)))
     {
         <MediaCard Data="@card"
                    DataRefreshed="@(() => RefreshData())"

ErsatzTV/Shared/MediaCard.razor

@@ -82,7 +82,7 @@
             return Placeholder;
         }
 
-        string first = sortTitle.Substring(0, 1).ToUpperInvariant();
+        string first = sortTitle?.Substring(0, 1).ToUpperInvariant() ?? string.Empty;
         return int.TryParse(first, out _) ? "#" : first;
     }