Improve logging in setPersistedClusterData. (#36581)

Before this change we would log setPersistedClusterData claiming we don't know
our VID/PID/etc, though chances are the data being passed in exactly contains
that information.

In the new setup, we update our state, then log.

Author: bzbarsky-apple

src/darwin/Framework/CHIP/MTRDevice_Concrete.mm

@@ -3799,7 +3799,14 @@ - (NSUInteger)unitTestAttributeCount
 
 - (void)setPersistedClusterData:(NSDictionary<MTRClusterPath *, MTRDeviceClusterData *> *)clusterData
 {
+    [self _doSetPersistedClusterData:clusterData];
+
+    // Log after we do the state update, so the log includes the data we just set.
     MTR_LOG("%@ setPersistedClusterData count: %lu", self, static_cast<unsigned long>(clusterData.count));
+}
+
+- (void)_doSetPersistedClusterData:(NSDictionary<MTRClusterPath *, MTRDeviceClusterData *> *)clusterData
+{
     if (!clusterData.count) {
         return;
     }