GroupByVariable: Add support for default values in schema (#105518)

* update schema

* update schema

* refactor property to singular naming

* bump scenes

* leave scenes to caret version

* add defaultValue to groupBy model

* typo

apps/dashboard/pkg/apis/dashboard/v2alpha1/dashboard_spec.cue

@@ -878,6 +878,7 @@ CustomVariableKind: {
 GroupByVariableSpec: {
 	name:        string | *""
 	datasource?: DataSourceRef
+	defaultValue?: VariableOption
 	current: VariableOption | *{
 		text:  ""
 		value: ""

apps/dashboard/pkg/apis/dashboard/v2alpha1/dashboard_spec_gen.go

@@ -1601,15 +1601,16 @@ func NewDashboardGroupByVariableKind() *DashboardGroupByVariableKind {
 // GroupBy variable specification
 // +k8s:openapi-gen=true
 type DashboardGroupByVariableSpec struct {
-	Name        string                    `json:"name"`
-	Datasource  *DashboardDataSourceRef   `json:"datasource,omitempty"`
-	Current     DashboardVariableOption   `json:"current"`
-	Options     []DashboardVariableOption `json:"options"`
-	Multi       bool                      `json:"multi"`
-	Label       *string                   `json:"label,omitempty"`
-	Hide        DashboardVariableHide     `json:"hide"`
-	SkipUrlSync bool                      `json:"skipUrlSync"`
-	Description *string                   `json:"description,omitempty"`
+	Name         string                    `json:"name"`
+	Datasource   *DashboardDataSourceRef   `json:"datasource,omitempty"`
+	DefaultValue *DashboardVariableOption  `json:"defaultValue,omitempty"`
+	Current      DashboardVariableOption   `json:"current"`
+	Options      []DashboardVariableOption `json:"options"`
+	Multi        bool                      `json:"multi"`
+	Label        *string                   `json:"label,omitempty"`
+	Hide         DashboardVariableHide     `json:"hide"`
+	SkipUrlSync  bool                      `json:"skipUrlSync"`
+	Description  *string                   `json:"description,omitempty"`
 }
 
 // NewDashboardGroupByVariableSpec creates a new DashboardGroupByVariableSpec object.