refactor(common): expose NgImage directive via a private API (#47082)

This commit exports experimental `NgImage` directive via a private API of the `@angular/common` package, so that it can be used acorss other Angular packages for testing purposes.

PR Close #47082

packages/common/src/common.ts

@@ -27,3 +27,4 @@ export {PLATFORM_BROWSER_ID as ɵPLATFORM_BROWSER_ID, PLATFORM_SERVER_ID as ɵPL
 export {VERSION} from './version';
 export {ViewportScroller, NullViewportScroller as ɵNullViewportScroller} from './viewport_scroller';
 export {XhrFactory} from './xhr';
+export {NgImageModule as ɵNgImageModule, NgImage as ɵNgImage, IMAGE_LOADER as ɵIMAGE_LOADER} from './directives/ng_image';

packages/common/src/directives/ng_image.ts

@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {Directive, Inject, InjectionToken, Input, SimpleChanges, ɵRuntimeError as RuntimeError} from '@angular/core';
+import {Directive, Inject, InjectionToken, Input, NgModule, SimpleChanges, ɵRuntimeError as RuntimeError} from '@angular/core';
 
 import {RuntimeErrorCode} from '../errors';
 
@@ -132,6 +132,17 @@ export class NgImage {
   }
 }
 
+/**
+ * Temporary NgModule that exports the `NgImage` directive.
+ * The module should not be needed once the `standalone` flag is supported as a public API.
+ */
+@NgModule({
+  declarations: [NgImage],
+  exports: [NgImage],
+})
+export class NgImageModule {
+}
+
 /***** Helpers *****/
 
 // Convert input value to integer.