[Fusion] Updated NonNullInputFieldIsInaccessibleRule (#9043)

Author: glen-84

src/HotChocolate/Fusion-vnext/src/Fusion.Composition/PostMergeValidationRules/NonNullInputFieldIsInaccessibleRule.cs

@@ -29,6 +29,8 @@ public void Handle(SchemaEvent @event, CompositionContext context)
                 .SelectMany(
                     s => s.Types
                         .OfType<MutableInputObjectTypeDefinition>()
+                        // Filter out input object types that do not exist in the composed schema.
+                        .Where(t => schema.Types.ContainsName(t.Name))
                         .SelectMany(
                             t => t.Fields.AsEnumerable().Select(f => new InputFieldInfo(f, t, s))));