TestConfigWatch is unstable

[lhy1024]

Flaky Test

Which jobs are failing

2023-11-15T11:36:13.2632858Z [2023/11/15 11:33:41.088 +00:00] [INFO] [cluster.go:1635] ["store has changed to serving"] [store-id=1] [store-address=mock://1]
2023-11-15T11:36:13.2634110Z     testutil.go:64: 
2023-11-15T11:36:13.2635148Z         	Error Trace:	/home/runner/work/pd/pd/pkg/utils/testutil/testutil.go:64
2023-11-15T11:36:13.2637233Z         	            				/home/runner/work/pd/pd/tests/integrations/mcs/scheduling/config_test.go:99
2023-11-15T11:36:13.2638418Z         	Error:      	Condition never satisfied
2023-11-15T11:36:13.2639221Z         	Test:       	TestConfig/TestConfigWatch
2023-11-15T11:36:13.2639892Z === RUN   TestConfig/TestSchedulerConfigWatch

CI link

https://github.com/lhy1024/pd/actions/runs/6876710714/job/18702868151

Reason for failure (if possible)

Anything else