fix faulty DB migration and remove default, server is the default

database/migrations/2024_08_12_155023_add_timezone_to_server_settings_table.php

@@ -9,7 +9,7 @@ class AddTimezoneToServerSettingsTable extends Migration
     public function up()
     {
         Schema::table('server_settings', function (Blueprint $table) {
-            $table->string('server_timezone')->default('UTC');
+            $table->string('server_timezone')->default('');
         });
     }