Service map backend links (elastic#107317)

Co-authored-by: Kibana Machine <42973632+kibanamachine@users.noreply.github.com>

Author: 2 people

x-pack/plugins/apm/common/service_map.ts

@@ -58,9 +58,9 @@ export interface Connection {
   destination: ConnectionNode;
 }
 
-export interface ServiceNodeStats {
-  avgMemoryUsage: number | null;
-  avgCpuUsage: number | null;
+export interface NodeStats {
+  avgMemoryUsage?: number | null;
+  avgCpuUsage?: number | null;
   transactionStats: {
     avgTransactionDuration: number | null;
     avgRequestsPerMinute: number | null;