[Fusion] Do not apply @Shareable to interfaces in compatibility mode (#8974)

Author: tobias-tengler

src/HotChocolate/Fusion-vnext/src/Fusion.Composition/SourceSchemaPreprocessor.cs

@@ -59,9 +59,9 @@ private void ApplyShareableDirectives()
     {
         foreach (var sourceSchema in schemas.Except([schema]))
         {
-            foreach (var type in schema.Types.OfType<MutableComplexTypeDefinition>())
+            foreach (var type in schema.Types.OfType<MutableObjectTypeDefinition>())
             {
-                if (!sourceSchema.Types.TryGetType<MutableComplexTypeDefinition>(type.Name, out var otherType))
+                if (!sourceSchema.Types.TryGetType<MutableObjectTypeDefinition>(type.Name, out var otherType))
                 {
                     continue;
                 }