Refactor _applyCustomAttributes function

lib/src/widgets/text_line.dart

@@ -37,6 +37,7 @@ class TextLine extends StatelessWidget {
   final DefaultStyles styles;
   final bool readOnly;
   final StyleBuilder? styleBuilder;
+
   @override
   Widget build(BuildContext context) {
     assert(debugCheckHasMediaQuery(context));
@@ -157,15 +158,14 @@ class TextLine extends StatelessWidget {
 
   TextStyle _applyCustomAttributes(
       TextStyle textStyle, Map<String, Attribute> attributes) {
-    if (styleBuilder != null) {
-      attributes.keys
-          .where((key) => !attributes.containsKey(key))
-          .forEach((key) {
-        /// Custom Attribute
-        final customAttr = styleBuilder!.call(key);
-        textStyle = textStyle.merge(customAttr);
-      });
+    if (styleBuilder == null) {
+      return textStyle;
     }
+    attributes.keys.where((key) => !attributes.containsKey(key)).forEach((key) {
+      /// Custom Attribute
+      final customAttr = styleBuilder!.call(key);
+      textStyle = textStyle.merge(customAttr);
+    });
     return textStyle;
   }