feat: Finalize bulk edits and reworked form fields

lib/features/edit_label/view/impl/add_tag_page.dart

@@ -35,6 +35,7 @@ class AddTagPage extends StatelessWidget {
             colorPickerType: ColorPickerType.materialPicker,
             initialValue: Color((Random().nextDouble() * 0xFFFFFF).toInt())
                 .withOpacity(1.0),
+            readOnly: true,
           ),
           FormBuilderCheckbox(
             name: Tag.isInboxTagKey,

lib/features/edit_label/view/impl/edit_tag_page.dart

@@ -32,7 +32,8 @@ class EditTagPage extends StatelessWidget {
             decoration: InputDecoration(
               label: Text(S.of(context)!.color),
             ),
-            colorPickerType: ColorPickerType.blockPicker,
+            colorPickerType: ColorPickerType.materialPicker,
+            readOnly: true,
           ),
           FormBuilderCheckbox(
             initialValue: tag.isInboxTag,