Chore: Deprecate FolderID from CountDashboardsInFolderRequest (#77804)

Deprecate FolderID from CountDashboardsInFolderRequest

pkg/services/dashboards/models.go

@@ -376,6 +376,7 @@ type CountDashboardsInFolderQuery struct {
 // to the store layer. The FolderID will be replaced with FolderUID when
 // dashboards are updated with parent folder UIDs.
 type CountDashboardsInFolderRequest struct {
+	// Deprecated: use FolderUID instead
 	FolderID int64
 	OrgID    int64
 }