Bug 1835656 - messaging_system.invalid_nested_data is on the wrong ping, r=chutten

Differential Revision: https://phabricator.services.mozilla.com/D179851

browser/components/newtab/metrics.yaml

@@ -1000,7 +1000,7 @@ messaging_system:
       - chutten@mozilla.com
     expires: never
     send_in_pings:
-      - metrics
+      - messaging-system
 
 
 messaging_system.attribution:

browser/components/newtab/test/xpcshell/test_AboutWelcomeTelemetry_glean.js

@@ -53,7 +53,7 @@ add_task(function test_weird_data() {
     Assert.equal(
       Glean.messagingSystem.invalidNestedData[
         invalidNestedDataKey
-      ].testGetValue(),
+      ].testGetValue("messaging-system"),
       1,
       "caught the invalid nested data"
     );