fix(@angular-devkit/schematics): address Node.js deprecation DEP0190

This approach has been recommanded by a Node.js member in nodejs/help#5063 (comment)

Closes #30821

Author: alan-agius4

packages/angular_devkit/schematics/tasks/package-manager/executor.ts

@@ -132,7 +132,7 @@ export default function (
         // Workaround for https://github.com/sindresorhus/ora/issues/136.
         discardStdin: process.platform != 'win32',
       }).start();
-      const childProcess = spawn(taskPackageManagerName, args, spawnOptions).on(
+      const childProcess = spawn(`${taskPackageManagerName} ${args.join(' ')}`, spawnOptions).on(
         'close',
         (code: number) => {
           if (code === 0) {

packages/angular_devkit/schematics/tasks/repo-init/executor.ts

@@ -41,7 +41,7 @@ export default function (
       };
 
       return new Promise<void>((resolve, reject) => {
-        spawn('git', args, spawnOptions).on('close', (code: number) => {
+        spawn(`git ${args.join(' ')}`, spawnOptions).on('close', (code: number) => {
           if (code === 0) {
             resolve();
           } else {