GC: Sharepoint selector added to the helper set. (#1900)

## Description
Adds SharePoint service to the GC helper set. 
<!-- Insert PR description-->

## Does this PR need a docs update or release note?
- [x] ⛔ No 

## Type of change

- [x] 🤖 Test

## Test Plan

- [x] ⚡ Unit test

src/internal/connector/graph_connector_helper_test.go

@@ -946,8 +946,9 @@ func getSelectorWith(service path.ServiceType) selectors.Selector {
 		s = selectors.ServiceExchange
 	case path.OneDriveService:
 		s = selectors.ServiceOneDrive
+	case path.SharePointService:
+		s = selectors.ServiceSharePoint
 	}
-	// TODO: ^ sharepoint
 
 	return selectors.Selector{
 		Service: s,