Make racy Darwin test less racy. (#27826)

We used a 1s min-interval and a 1s sleep to wait for reports.  Those could race
very easily.  Better to use a sleep longer than the min-interval.

Fixes #27507

src/darwin/Framework/CHIPTests/MTRXPCListenerSampleTests.m

@@ -1686,7 +1686,7 @@ - (void)test900_SubscribeClusterStateCache
 
  MTRClusterStateCacheContainer * clusterStateCacheContainer = [[MTRClusterStateCacheContainer alloc] init];
  NSLog(@"Setting up attribute cache subscription...");
- __auto_type * params = [[MTRSubscribeParams alloc] initWithMinInterval:@(1) maxInterval:@(60)];
+ __auto_type * params = [[MTRSubscribeParams alloc] initWithMinInterval:@(0) maxInterval:@(60)];
  [device subscribeWithQueue:queue
  params:params
  clusterStateCacheContainer:clusterStateCacheContainer