Update VTR Dashboard to use string-based target_type field

Change-Id: I7fe9933016935c53f2dc73438a4a2515bb72bf2b
diff --git a/xos/gui/src/app/components/vtr/vtr-dashboard.ts b/xos/gui/src/app/components/vtr/vtr-dashboard.ts
index 6f570e5..12158e0 100644
--- a/xos/gui/src/app/components/vtr/vtr-dashboard.ts
+++ b/xos/gui/src/app/components/vtr/vtr-dashboard.ts
@@ -50,7 +50,7 @@
     delete this.truckroll.backend_status;
     delete this.error;
 
-    this.truckroll.target_type_id = this.getSubscriberContentTypeId(this.truckroll.target_id);
+    this.truckroll.target_type = this.getSubscriberContentTypeId(this.truckroll.target_id);
     
     this.truckroll.subscriber_tenant_id = this.getVsgTenantForSubscriber(this.truckroll.target_id);