refactor(@angular-devkit/build-angular): lazy import inquirer

`inquirer` has a number of depedencies which slow down module resolution when importing (~138ms) by lazy loading this module we remove this overhead when prompts are not needed.

packages/angular_devkit/build_angular/src/utils/check-port.ts

@@ -6,7 +6,6 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import { prompt } from 'inquirer';
 import * as net from 'net';
 import { isTTY } from './tty';
 
@@ -36,15 +35,19 @@ export async function checkPort(port: number, host: string): Promise<number> {
           return;
         }
 
-        prompt({
-          type: 'confirm',
-          name: 'useDifferent',
-          message: `Port ${port} is already in use.\nWould you like to use a different port?`,
-          default: true,
-        }).then(
-          (answers) => (answers.useDifferent ? resolve(0) : reject(createInUseError(port))),
-          () => reject(createInUseError(port)),
-        );
+        import('inquirer')
+          .then(({ prompt }) =>
+            prompt({
+              type: 'confirm',
+              name: 'useDifferent',
+              message: `Port ${port} is already in use.\nWould you like to use a different port?`,
+              default: true,
+            }),
+          )
+          .then(
+            (answers) => (answers.useDifferent ? resolve(0) : reject(createInUseError(port))),
+            () => reject(createInUseError(port)),
+          );
       })
       .once('listening', () => {
         server.close();