Reuse amp_has_query_var() in AMP_Theme_Support::finish_init()

includes/class-amp-theme-support.php

@@ -327,20 +327,14 @@ public static function finish_init() {
  add_filter( 'template_include', [ __CLASS__, 'serve_paired_browsing_experience' ], PHP_INT_MAX );
  }
 
- $has_query_var = (
- isset( $_GET[ amp_get_slug() ] ) // phpcs:ignore WordPress.Security.NonceVerification.Recommended
- ||
- false !== get_query_var( amp_get_slug(), false )
- );
-
  if ( ! amp_is_request() ) {
  /*
  * Redirect to AMP-less URL if AMP is not available for this URL and yet the query var is present.
  * Temporary redirect is used for admin users because implied transitional mode and template support can be
  * enabled by user ay any time, so they will be able to make AMP available for this URL and see the change
  * without wrestling with the redirect cache.
  */
- if ( $has_query_var ) {
+ if ( amp_has_query_var() ) {
  self::redirect_non_amp_url( current_user_can( 'manage_options' ) ? 302 : 301 );
  }