Add isDefault to TaskGroup API (#128596)

* first pass at adding api

(cherry picked from commit 8a583c52ee)

* add task2 remaining changes

* remove unnecessary changes

* modify tasks.json directly for test

* reset tasks in test

* Fix compilation errors

Co-authored-by: Alex Ross <alros@microsoft.com>

src/vs/workbench/api/common/shared/tasks.ts

@@ -82,6 +82,11 @@ export interface TaskHandleDTO {
 	workspaceFolder: UriComponents | string;
 }
 
+export interface TaskGroupDTO {
+	isDefault?: boolean;
+	_id: string;
+}
+
 export interface TaskDTO {
 	_id: string;
 	name?: string;
@@ -89,7 +94,7 @@ export interface TaskDTO {
 	definition: TaskDefinitionDTO;
 	isBackground?: boolean;
 	source: TaskSourceDTO;
-	group?: string;
+	group?: TaskGroupDTO;
 	detail?: string;
 	presentationOptions?: TaskPresentationOptionsDTO;
 	problemMatchers: string[];