chore: remove shared ui files

Author: fulleni

lib/shared/constants/app_spacing.dart

@@ -2,4 +2,4 @@
 /// Exports application-wide constant definitions.
 library;
 
-export 'app_spacing.dart';
+export 'pagination_constants.dart';

lib/shared/constants/constants.dart

@@ -6,6 +6,3 @@ library;
 
 export 'constants/constants.dart';
 export 'extensions/extensions.dart';
-export 'theme/theme.dart';
-export 'utils/utils.dart';
-export 'widgets/widgets.dart';