fix: fixed codegen dropdown overflow

Author: alainjr10

lib/widgets/codegen_previewer.dart

@@ -135,7 +135,7 @@ class ViewCodePane extends StatelessWidget {
           child: Column(
             children: [
               SizedBox(
-                height: kHeaderHeight,
+                height: constraints.maxWidth > 340 ? kHeaderHeight : kTabHeight,
                 child: Row(
                   children: [
                     Expanded(

lib/widgets/dropdowns.dart

@@ -157,6 +157,7 @@ class DropdownButtonCodegenLanguage extends StatelessWidget {
   Widget build(BuildContext context) {
     final surfaceColor = Theme.of(context).colorScheme.surface;
     return DropdownButton<CodegenLanguage>(
+      isExpanded: true,
       focusColor: surfaceColor,
       value: codegenLanguage,
       icon: const Icon(