[Darwin] MTRDevice work blocks should only weakly reference self (project-chip#37757)

* [Darwin] MTRDevice work blocks should only weakly reference self

* Have invokeCommands call completion even when object is gone

* Revert "Have invokeCommands call completion even when object is gone"

This reverts commit ad01794.

Author: jtung-apple

src/darwin/Framework/CHIP/MTRDevice_Concrete.mm

@@ -708,8 +708,8 @@ - (void)_scheduleNextUpdate:(UInt64)nextUpdateInSeconds
 {
     mtr_weakify(self);
     dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t) (nextUpdateInSeconds * NSEC_PER_SEC)), self.queue, ^{
-        MTR_LOG_DEBUG("%@ Timer expired, start Device Time Update", self);
         mtr_strongify(self);
+        MTR_LOG_DEBUG("%@ Timer expired, start Device Time Update", self);
         if (self) {
             [self _performScheduledTimeUpdate];
         } else {
@@ -3659,8 +3659,12 @@ - (void)invokeCommands:(NSArray<NSArray<MTRCommandWithRequiredResponse *> *> *)c
     for (NSArray<MTRCommandWithRequiredResponse *> * commandGroup in [commands reverseObjectEnumerator]) {
         // We want to invoke all the commands in the group in order, propagating along the list of
         // current responses.  Build up that linked list of command invokes via chaining the completions.
+        mtr_weakify(self);
         for (MTRCommandWithRequiredResponse * command in [commandGroup reverseObjectEnumerator]) {
             auto commandInvokeBlock = ^(BOOL allSucceededSoFar, NSArray<MTRDeviceResponseValueDictionary> * previousResponses) {
+                mtr_strongify(self);
+                VerifyOrReturn(self, MTR_LOG_DEBUG("invokeCommands commandInvokeBlock called back with nil MTRDevice"));
+
                 [self invokeCommandWithEndpointID:command.path.endpoint
                                         clusterID:command.path.cluster
                                         commandID:command.path.command
@@ -3669,6 +3673,8 @@ - (void)invokeCommands:(NSArray<NSArray<MTRCommandWithRequiredResponse *> *> *)c
                             expectedValueInterval:nil
                                             queue:self.queue
                                        completion:^(NSArray<NSDictionary<NSString *, id> *> * responses, NSError * error) {
+                                           mtr_strongify(self);
+                                           VerifyOrReturn(self, MTR_LOG_DEBUG("invokeCommands invokeCommandWithEndpointID completion called back with nil MTRDevice"));
                                            if (error != nil) {
                                                nextCompletion(NO, [previousResponses arrayByAddingObject:@ {
                                                    MTRCommandPathKey : command.path,
@@ -3701,6 +3707,9 @@ - (void)invokeCommands:(NSArray<NSArray<MTRCommandWithRequiredResponse *> *> *)c
         }
 
         auto commandGroupInvokeBlock = ^(BOOL allSucceededSoFar, NSArray<MTRDeviceResponseValueDictionary> * previousResponses) {
+            mtr_strongify(self);
+            VerifyOrReturn(self, MTR_LOG_DEBUG("invokeCommands commandGroupInvokeBlock called back with nil MTRDevice"));
+
             if (allSucceededSoFar == NO) {
                 // Don't start a new command group if something failed in the
                 // previous one.  Note that we might be running on self.queue here, so make sure we