Replace null material sets during item conversion with valid material sets.

Author: Lunaretic

xivModdingFramework/Mods/RootCloner.cs

@@ -353,6 +353,19 @@ public static async Task CloneRoot(XivDependencyRoot Source, XivDependencyRoot D
                 {
                     ProgressReporter.Report("Copying metdata...");
                 }
+
+                // Poke through the variants and adjust any that point to null Material Sets to instead use a valid one.
+                var valid = newMetadata.ImcEntries.FirstOrDefault(x => x.MaterialSet != 0).MaterialSet;
+
+                for(int i = 0; i < newMetadata.ImcEntries.Count; i++)
+                {
+                    var entry = newMetadata.ImcEntries[i];
+                    if (entry.MaterialSet == 0)
+                    {
+                        entry.MaterialSet = valid;
+                    }
+                }
+
                 // Save the new Metadata file.
                 await ItemMetadata.SaveMetadata(newMetadata, ApplicationSource);