Remove no-longer-correct comment. (#41034)

We now have a controller:reachedCommissioningStage: notification.

src/darwin/Framework/CHIP/MTRCommissioningOperation.mm

diff --git a/src/darwin/Framework/CHIP/MTRCommissioningOperation.mm b/src/darwin/Framework/CHIP/MTRCommissioningOperation.mm
index 7941609..64f8a57 100644
--- a/src/darwin/Framework/CHIP/MTRCommissioningOperation.mm
+++ b/src/darwin/Framework/CHIP/MTRCommissioningOperation.mm
@@ -351,11 +351,6 @@
     });
 }
 
-// TODO: There is currently no way to know when a commissioning stage _starts_, so we
-// don't have a good way to create MTRCommissioningStageWiFiScanStart and
-// MTRCommissioningStageThreadScanStart notifications.  This will need changes
-// to the C++ DevicePairingDelegate.
-
 #pragma mark - MTRDeviceControllerDelegate_Internal implementatation
 
 - (void)controller:(MTRDeviceController *)controller