build: Add pullapprove verification tool to dev-infra-private package (#35911)

Migrates pullapprove verification tool to be available in the dev-infra-private
package

PR Close #35911

dev-infra/cli.ts

@@ -5,10 +5,16 @@
  * Use of this source code is governed by an MIT-style license that can be
  * found in the LICENSE file at https://angular.io/license
  */
+import {verify} from './pullapprove/verify';
+
 const args = process.argv.slice(2);
 
+
 // TODO(josephperrott): Set up proper cli flag/command handling
-switch(args[0]) {
+switch (args[0]) {
+  case 'pullapprove:verify':
+    verify();
+    break;
   default:
     console.info('No commands were matched');
 }