Refactor color management and UI components for consistency

- Updated color references in various widgets to use the new `opaquePrimary` color for better visual consistency.
- Refactored `ColorsManager` to improve color definitions and removed redundant color declarations.
- Enhanced UI elements across multiple dialogs and widgets to ensure a cohesive design language.

This change promotes maintainability and aligns with the updated color scheme.

lib/pages/routines/widgets/delete_scene.dart

@@ -39,7 +39,8 @@ class DeleteSceneWidget extends StatelessWidget {
                           ),
                         ),
                       ),
-                      Container(width: 1, height: 50, color: ColorsManager.greyColor),
+                      Container(
+                          width: 1, height: 50, color: ColorsManager.greyColor),
                       InkWell(
                         onTap: () {
                           context.read<RoutineBloc>().add(const DeleteScene());
@@ -51,7 +52,7 @@ class DeleteSceneWidget extends StatelessWidget {
                           child: Text(
                             'Confirm',
                             style: Theme.of(context).textTheme.bodyMedium!.copyWith(
-                                  color: ColorsManager.primaryColorWithOpacity,
+                                  color: ColorsManager.opaquePrimary,
                                 ),
                           ),
                         ),