Nested folders: Provide count of all descendant dashboards and folders (#67184)

* Add a method for getting descendant folders
* Include dashboard count for descendant folders
* Return subfolder count
* Replace references to children with descendants
* Update openapi specs
* Add test for descendant counts
* Add logging to GetDescendantCounts

pkg/services/folder/foldertest/foldertest.go

@@ -7,10 +7,10 @@ import (
 )
 
 type FakeService struct {
-	ExpectedFolders        []*folder.Folder
-	ExpectedFolder         *folder.Folder
-	ExpectedError          error
-	ExpectedChildrenCounts map[string]int64
+	ExpectedFolders          []*folder.Folder
+	ExpectedFolder           *folder.Folder
+	ExpectedError            error
+	ExpectedDescendantCounts map[string]int64
 }
 
 func NewFakeService() *FakeService {
@@ -51,6 +51,6 @@ func (s *FakeService) RegisterService(service folder.RegistryService) error {
 	return s.ExpectedError
 }
 
-func (s *FakeService) GetChildrenCounts(ctx context.Context, cmd *folder.GetChildrenCountsQuery) (folder.ChildrenCounts, error) {
-	return s.ExpectedChildrenCounts, s.ExpectedError
+func (s *FakeService) GetDescendantCounts(ctx context.Context, cmd *folder.GetDescendantCountsQuery) (folder.DescendantCounts, error) {
+	return s.ExpectedDescendantCounts, s.ExpectedError
 }