Fix getAttribute

Author: diegomvh

projects/angular-odata/src/lib/models/model.ts

@@ -852,13 +852,13 @@ export class ODataModel<T> {
     }
   }
 
-  getAttribute<M extends ODataModel<keyof T>>(
+  getAttribute<M extends ODataModel<any>>(
     name: keyof T,
   ): M | null;
-  getAttribute<C extends ODataCollection<keyof T, ODataModel<keyof T>>>(
+  getAttribute<C extends ODataCollection<any, ODataModel<any>>>(
     name: keyof T,
   ): C | null;
-  getAttribute<P extends T[keyof T]>(
+  getAttribute<P>(
     name: keyof T, 
   ): (P extends (infer U)[] ? ODataCollection<U, ODataModel<U> & ModelInterface<U>> : 
     P extends object ? ODataModel<P> & ModelInterface<P> : P) | null;