Fix bug when loading server owner dropdown

closes pterodactyl#1137

Author: DaneEveritt

CHANGELOG.md

@@ -7,6 +7,7 @@ This project follows [Semantic Versioning](http://semver.org) guidelines.
 ### Fixed
 * Fixes an issue with the sidebar logo not working correctly in some browsers due to the CSS being assigned.
 * Fixes a bunch of typos through the code base.
+* Fixes a bug when attempting to load the dropdown menu for server owner in some cases.
 
 ### Added
 * Added a new client API endpoint for gathering the utilization stats for servers including disk, cpu, and memory. `GET /api/client/servers/<id>/utilization`

app/Contracts/Repository/UserRepositoryInterface.php

@@ -18,8 +18,8 @@ public function getAllUsersWithCounts(): LengthAwarePaginator;
     /**
      * Return all matching models for a user in a format that can be used for dropdowns.
      *
-     * @param string $query
+     * @param string|null $query
      * @return \Illuminate\Support\Collection
      */
-    public function filterUsersByQuery(string $query): Collection;
+    public function filterUsersByQuery(?string $query): Collection;
 }

app/Repositories/Eloquent/UserRepository.php

@@ -37,10 +37,10 @@ public function getAllUsersWithCounts(): LengthAwarePaginator
     /**
      * Return all matching models for a user in a format that can be used for dropdowns.
      *
-     * @param string $query
+     * @param string|null $query
      * @return \Illuminate\Support\Collection
      */
-    public function filterUsersByQuery(string $query): Collection
+    public function filterUsersByQuery(?string $query): Collection
     {
         $this->setColumns([
             'id', 'email', 'username', 'name_first', 'name_last',