Remove Win MDM "Status on a Status" from osquery perf (#43940)

Estimate ~5% load improvement.

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

* **Bug Fixes**
* Fixed MDM command handling in the performance testing agent to
properly skip duplicate status responses.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

cmd/osquery-perf/agent.go

@@ -1418,6 +1418,12 @@ func (a *agent) runWindowsMDMLoop() {
 		}
 
 		for _, c := range cmds {
+			// Skip the server's own <Status> entries. MS-MDM's "Status on a Status" is only for auth-renegotiation edge cases (see
+			// https://learn.microsoft.com/en-us/openspecs/windows_protocols/ms-mdm/36b1a4d9-fd93-48ce-b865-6a9d396c52a4
+			// "While this case is not usually encountered"); real Windows does not emit Status-on-Status during normal check-ins.
+			if c.Verb == fleet.CmdStatus {
+				continue
+			}
 			a.stats.IncrementMDMCommandsReceived()
 
 			status := syncml.CmdStatusOK