Enhance user plan management and update related endpoints

- Added new configuration options for user plans in `.env.example`, including `Plans__MaxCustomConfigCount` and `Plans__MinCustomConfigCount`.
- Introduced `MapPlanEndpoints` in `Program.cs` to handle plan-related API routes.
- Implemented `SetUserPlan` endpoint in `RoleEndpoints` to allow admins to assign plans to users.
- Removed deprecated role request approval endpoints from `AdminSupportEndpoints`.
- Updated `ITelegramNotifier` and related classes to reflect changes in role request handling and payment notifications.
- Refactored role management commands to remove `MaxConfigs` and focus on `MaxIpLimit` and billing settings.
- Enhanced billing request handling to accommodate plan changes instead of role changes.
- Updated various interfaces and command handlers to support new plan management features.

backend/src/PnvPanel.Application/Admin/Roles/UpdateRoleCommandHandler.cs

@@ -13,7 +13,6 @@ public sealed class UpdateRoleCommandHandler(IRoleService roleService)
     ) =>
         roleService.UpdateRoleAsync(
             command.RoleId,
-            command.MaxConfigs,
             command.MaxIpLimit,
             command.BillingEnabled,
             cancellationToken