refactor(@angular/cli): handle undefined ng add collection name

Fixes an issue where JSON help extraction fails if the `ng add` collection name is undefined.

Author: alan-agius4

packages/angular/cli/src/commands/add/cli.ts

@@ -100,7 +100,11 @@ export default class AddCommandModule
       // `ng add @angular/localize -- --package-options`.
       .strict(false);
 
-    const collectionName = await this.getCollectionName();
+    const collectionName = this.getCollectionName();
+    if (!collectionName) {
+      return localYargs;
+    }
+
     const workflow = this.getOrCreateWorkflowForBuilder(collectionName);
 
     try {
@@ -401,8 +405,11 @@ export default class AddCommandModule
     return false;
   }
 
-  private async getCollectionName(): Promise<string> {
+  private getCollectionName(): string | undefined {
     let [, collectionName] = this.context.args.positional;
+    if (!collectionName) {
+      return undefined;
+    }
 
     // The CLI argument may specify also a version, like `ng add @my/[email protected]`,
     // but here we need only the name of the package, like `@my/lib`