Apply fixes from StyleCI

Author: StyleCIBot

migrations/2023_07_08_000001_update_polls_discussion_relation_to_first_post.php

@@ -10,7 +10,6 @@
  */
 
 use Illuminate\Database\Query\JoinClause;
-use Illuminate\Database\Schema\Blueprint;
 use Illuminate\Database\Schema\Builder;
 
 // Split 1/2 of 2023_07_08_000001_update_polls_discussion_relation_to_first_post.php

migrations/2023_07_08_000002_add_polls_post_id_foreign.php

@@ -9,10 +9,8 @@
  * file that was distributed with this source code.
  */
 
-use Illuminate\Database\Query\JoinClause;
 use Illuminate\Database\Schema\Blueprint;
 use Illuminate\Database\Schema\Builder;
-use Illuminate\Support\Arr;
 
 // Split 2/2 of 2023_07_08_000001_update_polls_discussion_relation_to_first_post.php
 return [