Intent of TestWatchCreateForExistingNamespace

All 4 exact tests in this concept. Every test is marked by where it enters the hierarchy.

go.temporal.io/ 4 tests
- server/ 4 tests
  - common/ 4 tests
    
    namespace/ 4 tests
    
    nsregistry/ 4 tests
    
    TestRegistryWatchSuite/ 4 tests
    
    go.temporal.io/server/common/namespace/nsregistry/TestRegistryWatchSuite/TestWatchCreateForExistingNamespace Introduced here
    
    go.temporal.io/server/common/namespace/nsregistry/TestRegistryWatchSuite/TestWatchEvents Inherited registry.go ×1
    
    go.temporal.io/server/common/namespace/nsregistry/TestRegistryWatchSuite/TestWatchStaleUpdateIgnored Inherited registry.go ×1
    
    go.temporal.io/server/common/namespace/nsregistry/TestRegistryWatchSuite/TestWatchUpdateWithoutStateChange Inherited TestWatchUpdateWithoutStateChange