fixup! chore(migration): [custom_fields] change available_options column to nullable

Author: moon-brillar

database/migrations/2023_05_18_002949_create_custom_fields_table.php

@@ -25,7 +25,7 @@ public function up()
             $table->string('model_class');
             $table->unsignedBigInteger('contextable_id')->nullable();
             $table->string('contextable_type')->nullable();
-            $table->unique(['key', 'model_class', 'contextable_type', 'contextable_id']);
+            $table->unique(['key', 'model_class', 'contextable_type', 'contextable_id'], 'custom_fields_key_model_class_contextable_unique');
             $table->timestamps();
         });
     }