Remove split between GQL schema & class types in `ResourcesHost.getIn…

…terfaces`

The GQL schema is always available now that my PR got merged.
The class types (aka `EnhancedResource.interfaces`) now works for IntersectTypes

Still, having the split between our class type inheritance and GQL schema gives me pause for thought.
They should be in sync, so maybe one should just be picked always over the other?
I guess class types could still be private, not exposed to GQL schema.
And GQL schema needs the app to be booted & use service, instead of just accessing on EnhancedResource...

src/core/resources/resources.host.ts

@@ -131,34 +131,8 @@ export class ResourcesHost {
       : EnhancedResource.of(ref);
   }
 
-  getInterfaces(
-    resource: EnhancedResource<any>,
-  ): ReadonlyArray<EnhancedResource<any>> {
-    // Use interfaces from GQL schema if it's available.
-    // Otherwise, fallback to the interfaces from DTO class hierarchy.
-    // The former doesn't work with CLI.
-    // The latter doesn't work for IntersectionTypes.
-    // Hoping to resolve with https://github.com/nestjs/graphql/pull/2435
-    try {
-      // eslint-disable-next-line @typescript-eslint/no-unused-expressions
-      this.gqlSchema.schema;
-    } catch (e) {
-      return this.getInterfacesFromClassType(resource);
-    }
-    return this.getInterfacesFromGQLSchema(resource);
-  }
-
   @CachedByArg()
-  private getInterfacesFromClassType(
-    resource: EnhancedResource<any>,
-  ): ReadonlyArray<EnhancedResource<any>> {
-    const map = this.getEnhancedMap();
-    const resSet = new Set<EnhancedResource<any>>(Object.values(map));
-    return [...resource.interfaces].filter((i) => resSet.has(i));
-  }
-
-  @CachedByArg()
-  private getInterfacesFromGQLSchema(
+  getInterfaces(
     resource: EnhancedResource<any>,
   ): ReadonlyArray<EnhancedResource<any>> {
     const { schema } = this.gqlSchema;