Fix DIY migration failing to fetch migration key and throwing 403 on page reload (#40270)

* Remove check for read flag from migration key get api checks

* Changelog - Remove read check from migration key access checks

* Remove key_is_read_option_name altogether

Author: Imran92

projects/packages/jetpack-mu-wpcom/changelog/fix-migration-diy-throws-403-on-page-reload

@@ -0,0 +1,4 @@
+Significance: patch
+Type: fixed
+
+Fix migration key fetch failing when DIY migration page is reloaded

projects/packages/jetpack-mu-wpcom/src/features/wpcom-endpoints/class-wpcom-rest-api-v2-endpoint-site-migration-wpcom-migration-key.php

@@ -12,13 +12,6 @@
  * @hide-in-jetpack
  */
 class WPCOM_REST_API_V2_Endpoint_Site_Migration_WPCOM_Migration_Key extends WP_REST_Controller {
-	/**
-	 * Option name that tracks wether the key has been read or not.
-	 * The only possible value for the option is 'read'.
-	 *
-	 * @var string
-	 */
-	protected $key_is_read_option_name = 'wpcom_site_migration_wpcom_migration_key_read';
 
 	/**
 	 * Class constructor
@@ -73,10 +66,6 @@ public function can_access() {
 			return false;
 		}
 
-		if ( 'read' === get_option( $this->key_is_read_option_name, false ) ) {
-			return false;
-		}
-
 		return true;
 	}
 
@@ -89,8 +78,6 @@ private function get_migration_key() {
 		$wpcom_migration_settings = new WPCOMWPSettings();
 		$wpcom_migration_info     = new WPCOMInfo( $wpcom_migration_settings );
 
-		update_option( $this->key_is_read_option_name, 'read' );
-
 		return $wpcom_migration_info->getConnectionKey();
 	}