feat: update shimmer loading components to remove const constructors for better flexibility

apps/mobile/packages/features/staff/clock_in/lib/src/presentation/widgets/clock_in_page_skeleton/date_selector_skeleton.dart

@@ -18,7 +18,7 @@ class DateSelectorSkeleton extends StatelessWidget {
               margin: const EdgeInsets.symmetric(
                 horizontal: UiConstants.space1,
               ),
-              child: const UiShimmerBox(
+              child: UiShimmerBox(
                 width: double.infinity,
                 height: 80,
                 borderRadius: UiConstants.radiusLg,

apps/mobile/packages/features/staff/clock_in/lib/src/presentation/widgets/clock_in_page_skeleton/swipe_action_skeleton.dart

@@ -8,7 +8,7 @@ class SwipeActionSkeleton extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    return const UiShimmerBox(
+    return UiShimmerBox(
       width: double.infinity,
       height: 60,
       borderRadius: UiConstants.radiusLg,

apps/mobile/packages/features/staff/profile/lib/src/presentation/widgets/profile_page_skeleton/reliability_score_skeleton.dart

@@ -30,7 +30,7 @@ class ReliabilityScoreSkeleton extends StatelessWidget {
           ),
           const SizedBox(height: UiConstants.space2),
           // Progress bar placeholder
-          const UiShimmerBox(
+          UiShimmerBox(
             width: double.infinity,
             height: 8,
             borderRadius: UiConstants.radiusSm,