fix: default template on iOS (#30571)

Summary:
Recently introduced steps to run Hermes accidentally removed `!` from the `use_react_native`, causing `pod install` to fail with an error.

## Changelog

[INTERNAL] [iOS] - Fix Podfle in default template

Pull Request resolved: #30571

Test Plan: Run `pod install` with this file and it should work.

Reviewed By: appden

Differential Revision: D25537263

Pulled By: TheSavior

fbshipit-source-id: da7f21775cbe641e34aded87a92c696539f4d5c3

template/ios/Podfile

@@ -6,7 +6,7 @@ platform :ios, '10.0'
 target 'HelloWorld' do
   config = use_native_modules!
 
-  use_react_native(
+  use_react_native!(
     :path => config[:reactNativePath],
     # to enable hermes on iOS, change `false` to `true` and then install pods
     :hermes_enabled => false