remove experimental prefix and add instance metadata example plugin by default

Signed-off-by: aramissennyeydd <aramis.sennyey@doordash.com>

packages/backend-app-api/src/wiring/BackendInitializer.test.ts

@@ -27,7 +27,7 @@ import {
   createBackendFeatureLoader,
 } from '@backstage/backend-plugin-api';
 import { BackendInitializer } from './BackendInitializer';
-import { EXPERIMENTAL_instanceMetadataServiceRef } from '@backstage/backend-plugin-api/alpha';
+import { instanceMetadataServiceRef } from '@backstage/backend-plugin-api/alpha';
 
 class MockLogger {
   debug() {}
@@ -743,7 +743,7 @@ describe('BackendInitializer', () => {
       register(reg) {
         reg.registerInit({
           deps: {
-            instanceMetadata: EXPERIMENTAL_instanceMetadataServiceRef,
+            instanceMetadata: instanceMetadataServiceRef,
           },
           async init({ instanceMetadata }) {
             expect(instanceMetadata.getInstalledFeatures()).toEqual([

packages/backend-app-api/src/wiring/BackendInitializer.ts

@@ -36,7 +36,7 @@ import type {
 import type { InternalServiceFactory } from '../../../backend-plugin-api/src/services/system/types';
 import { ForwardedError, ConflictError } from '@backstage/errors';
 import {
-  EXPERIMENTAL_instanceMetadataServiceRef,
+  instanceMetadataServiceRef,
   featureDiscoveryServiceRef,
   BackendFeatureMeta,
 } from '@backstage/backend-plugin-api/alpha';
@@ -128,7 +128,7 @@ function createInstanceMetadataServiceFactory(
     })
     .flat();
   return createServiceFactory({
-    service: EXPERIMENTAL_instanceMetadataServiceRef,
+    service: instanceMetadataServiceRef,
     deps: {},
     factory: async () => ({ getInstalledFeatures: () => installedFeatures }),
   });