Make the appengine service name sweepable in the test compute region network endpoint (#11993) (#820)

[upstream:3c185c1ca0295944e18299a57842d0b44340f62e]

Signed-off-by: Modular Magician <[email protected]>

Author: modular-magician

region_network_endpoint_group_appengine/main.tf

@@ -11,7 +11,7 @@ resource "google_compute_region_network_endpoint_group" "appengine_neg" {
 
 resource "google_app_engine_flexible_app_version" "appengine_neg" {
   version_id = "v1"
-  service    = "appengine-network-endpoint-group"
+  service    = "appengine-neg-${local.name_suffix}"
   runtime    = "nodejs"
   flexible_runtime_settings {
     operating_system = "ubuntu22"