Add validation on part no qty field

lib/extensions/text_extensions.dart

@@ -27,7 +27,7 @@ extension TextStyles on String {
 
   Text overline(BuildContext context) => getTextWithStyle(this, AppTextStyles.overline, context.isDark ? AppColor.neutral10 : AppColor.neutral20);
 
-  Text getTextWithStyle(String string, TextStyle style, Color color) => Text(string, style: style.copyWith(color: color));
+  Text getTextWithStyle(String string, TextStyle style, Color color) => Text(string ?? "", style: style.copyWith(color: color));
 }
 
 extension CustomText on Text {

lib/views/pages/user/requests/work_order/part_no_button.dart

@@ -78,7 +78,7 @@ class _PartNoButtonState extends State<PartNoButton> {
             labelText: context.translation.quantity,
             textInputType: TextInputType.number,
             backgroundColor: context.isDark ? AppColor.neutral20 : AppColor.neutral30,
-            enable: current != null,
+            enable: current != null && current.sparePart?.id != null,
             validator: (value) => value == null || value.isEmpty
                 ? context.translation.requiredField
                 : Validator.isNumeric(value)

lib/views/widgets/images/multi_image_picker_item.dart

@@ -68,7 +68,7 @@ class MultiFilesPickerItem extends StatelessWidget {
                 } else {
                   if (!await launchUrl(Uri.parse(file.path), mode: LaunchMode.externalApplication)) {
                     Fluttertoast.showToast(msg: "UnExpected Error with file.");
-                    throw Exception('Could not launch ');
+                    throw Exception('Could not launch');
                   }
                 }
               },