unify isEnum() condition

Author: cebe

src/lib/ColumnToCode.php

@@ -226,7 +226,7 @@ public function isJson():bool
 
     public function isEnum():bool
     {
-        return !empty($this->column->enumValues) && empty($this->column->xDbType);
+        return BaseMigrationBuilder::isEnum($this->column);
     }
 
     public function isDecimal()

src/lib/migrations/BaseMigrationBuilder.php

@@ -479,10 +479,7 @@ public function newColStr(string $tableAlias, \cebe\yii2openapi\db\ColumnSchema
 
     public static function isEnum(\yii\db\ColumnSchema $columnSchema): bool
     {
-        if (!empty($columnSchema->enumValues) && is_array($columnSchema->enumValues) && empty($columnSchema->xDbType)) {
-            return true;
-        }
-        return false;
+        return !empty($columnSchema->enumValues) && is_array($columnSchema->enumValues) && empty($columnSchema->xDbType);
     }
 
     public static function isEnumValuesChanged(