Fix duplication for Octane (#51)

* Update SetTheme.php

Fixes Octane duplication issue

* Update SetTheme.php

Better approach! Dont even add if its already there

src/Http/Middleware/SetTheme.php

@@ -33,15 +33,24 @@ public function handle(Request $request, Closure $next): Response
  return $next($request);
  }
 
- $panel->userMenuItems(
- ThemesPlugin::canView() ?
- [
- MenuItem::make('Themes')
- ->label(__('themes::themes.themes'))
- ->icon(config('themes.icon'))
- ->url(ThemesPage::getUrl()),
- ] : []
- );
+ /**
+ * Important for Laravel Octane!
+ * 
+ * Check if item already exists before adding it
+ * to the menu items.
+ */
+ if(!isset($panel->getUserMenuItems()[__('themes::themes.themes')])){
+ $panel->userMenuItems(
+ ThemesPlugin::canView() ?
+ [
+ __('themes::themes.themes') =>
+ MenuItem::make('Themes')
+ ->label(__('themes::themes.themes'))
+ ->icon(config('themes.icon'))
+ ->url(ThemesPage::getUrl()),
+ ] : []
+ );
+ }
 
  FilamentColor::register($themes->getCurrentThemeColor());