feat: enhance product ticket selector and vertical cart card components

- Refactor ProductTicketSelectorComponent to improve variant selection logic and error handling.
- Introduce a new signal for variant attributes and manage variant loading more efficiently.
- Update the UI to reflect saving state in ProductVerticalWithCartCardComponent, preventing actions while saving.
- Adjust button text based on saving state for better user feedback.

src/app/core/services/catalog/catalog.interface.ts

@@ -118,6 +118,7 @@ export interface CatalogFeaturedItemVariant {
 }
 
 export interface CatalogVariantOptionsResponse {
+  variants: CatalogFeaturedItemVariant[];
   selectors: CatalogVariantSelector[];
   selected_values: Record<string, string | string[]>;
   resolved_variant: CatalogFeaturedItemVariant | null;