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/utils/snack_bar.dart

@@ -22,7 +22,7 @@ class CustomSnackBar {
         content: Row(mainAxisAlignment: MainAxisAlignment.center, children: [
           const Icon(
             Icons.check_circle,
-            color: ColorsManager.whiteColors,
+            color: ColorsManager.white,
             size: 32,
           ),
           const SizedBox(
@@ -30,10 +30,8 @@ class CustomSnackBar {
           ),
           Text(
             message,
-            style: Theme.of(currentContext)
-                .textTheme
-                .bodySmall!
-                .copyWith(fontSize: 14, fontWeight: FontWeight.w500, color: Colors.green),
+            style: Theme.of(currentContext).textTheme.bodySmall!.copyWith(
+                fontSize: 14, fontWeight: FontWeight.w500, color: Colors.green),
           )
         ]),
       );
@@ -59,10 +57,8 @@ class CustomSnackBar {
           ),
           Text(
             message,
-            style: Theme.of(currentContext)
-                .textTheme
-                .bodySmall!
-                .copyWith(fontSize: 14, fontWeight: FontWeight.w500, color: Colors.green),
+            style: Theme.of(currentContext).textTheme.bodySmall!.copyWith(
+                fontSize: 14, fontWeight: FontWeight.w500, color: Colors.green),
           )
         ]),
       );