fix(windows): early return when download meta data invalid

is invalid or the version is not newer then currently installed

windows/src/desktop/kmshell/main/Keyman.System.UpdateStateMachine.pas

@@ -776,6 +776,7 @@ begin
       // Return to Idle state
       bucStateContext.RemoveCachedFiles;
       ChangeState(IdleState);
+      Exit;
     end;
 
     DownloadResult := DownloadUpdatesBackground;