Make sure to ignore setDeviceControllerDelegate calls on non-running controllers. (#22778)

Otherwise we can end up with null-derefs trying to touch members that
no longer exist.

Fixes #22776

Author: bzbarsky-apple

src/darwin/Framework/CHIP/MTRDeviceController.mm

@@ -535,7 +535,11 @@ - (void)removeDevice:(MTRDevice *)device
 
 - (void)setDeviceControllerDelegate:(id<MTRDeviceControllerDelegate>)delegate queue:(dispatch_queue_t)queue
 {
+    VerifyOrReturn([self checkIsRunning]);
+
     dispatch_async(_chipWorkQueue, ^{
+        VerifyOrReturn([self checkIsRunning]);
+
         self->_deviceControllerDelegateBridge->setDelegate(self, delegate, queue);
     });
 }