fix(material/schematics): remove node_modules prefix from prebuilt theme

The Angular CLI supports resolving node modules without the need of specifying `node_modules` directory. This also needed to add support for Yarn PNP which doesn't create a `node_modules` directory.

Closes #25242

(cherry picked from commit be0b688)

Author: alan-agius4

integration/yarn-pnp-compat/angular.json

@@ -27,7 +27,7 @@
             "tsConfig": "tsconfig.app.json",
             "inlineStyleLanguage": "scss",
             "assets": ["src/favicon.ico", "src/assets"],
-            "styles": ["src/styles.scss"],
+            "styles": ["@angular/material/prebuilt-themes/indigo-pink.css", "src/styles.scss"],
             "scripts": []
           },
           "configurations": {
@@ -90,10 +90,7 @@
             "karmaConfig": "karma.conf.js",
             "inlineStyleLanguage": "scss",
             "assets": ["src/favicon.ico", "src/assets"],
-            "styles": [
-              "./node_modules/@angular/material/prebuilt-themes/indigo-pink.css",
-              "src/styles.scss"
-            ],
+            "styles": ["@angular/material/prebuilt-themes/indigo-pink.css", "src/styles.scss"],
             "scripts": []
           }
         }

integration/yarn-pnp-compat/package.json

@@ -26,8 +26,8 @@
     "zone.js": "~0.11.4"
   },
   "devDependencies": {
-    "@angular-devkit/build-angular": "^15.0.0-next.0",
-    "@angular/cli": "^15.0.0-next.0",
+    "@angular-devkit/build-angular": "^15.0.0-next.6",
+    "@angular/cli": "^15.0.0-next.6",
     "@angular/compiler-cli": "^15.0.0-next.0",
     "@types/jasmine": "~3.10.0",
     "@types/node": "^12.11.1",

integration/yarn-pnp-compat/src/test.ts

@@ -7,21 +7,5 @@ import {
   platformBrowserDynamicTesting,
 } from '@angular/platform-browser-dynamic/testing';
 
-declare const require: {
-  context(
-    path: string,
-    deep?: boolean,
-    filter?: RegExp,
-  ): {
-    <T>(id: string): T;
-    keys(): string[];
-  };
-};
-
 // First, initialize the Angular testing environment.
 getTestBed().initTestEnvironment(BrowserDynamicTestingModule, platformBrowserDynamicTesting());
-
-// Then we find all the tests.
-const context = require.context('./', true, /\.spec\.ts$/);
-// And load the modules.
-context.keys().map(context);