fix(ivy): @Inject should not overwrite an existing ngInjectableDef (#27278)

There is no test in this diff because I've made a failing test pass.

PR Close #27278

packages/core/src/render3/jit/injectable.ts

@@ -27,6 +27,10 @@ export function compileInjectable(type: Type<any>, srcMeta?: Injectable): void {
   const meta: Injectable = srcMeta || {providedIn: null};
 
   let def: any = null;
+
+  // if NG_INJECTABLE_DEF is already defined on this class then don't overwrite it
+  if (type.hasOwnProperty(NG_INJECTABLE_DEF)) return;
+
   Object.defineProperty(type, NG_INJECTABLE_DEF, {
     get: () => {
       if (def === null) {