Replace 'flutter pub get' with 'flutter pub add' for url_launcher in deploy_live_preview.yml

Author: Harshit2756

.github/workflows/deploy_live_preview.yml

@@ -45,7 +45,7 @@ jobs:
           flutter pub add device_preview
           flutter pub add device_preview_screenshot
           flutter pub add font_awesome_flutter
-          flutter pub get url_launcher
+          flutter pub add url_launcher
           flutter pub get
 
       - name: Update device_preview_button.dart for preview