ClearSnapshot should clean up watches

[jpeach]

go-control-plane/pkg/cache/v3/simple.go

Lines 264 to 270 in 5284181

	func (cache *snapshotCache) ClearSnapshot(node string) {
	cache.mu.Lock()
	defer cache.mu.Unlock()
	delete(cache.snapshots, node)
	delete(cache.status, node)
	}

ClearSnapshot deletes the status for a node, but the states can have watches in it that will now never get triggered. Perhaps the right approach is to close the watch channels. However, looking at the SOTW server, closing any of the watch channels will make the stream handler error out.

So it's not obvious to me what the behavior of watches should be when a snapshot is cleared, but it seems something should happen since a subsequent SetSnapshot would not trigger any watches.

[github-actions]

This issue has been automatically marked as stale because it has not had activity in the last 30 days. It will be closed in the next 7 days unless it is tagged "help wanted" or "no stalebot" or other activity occurs. Thank you for your contributions.

[jpeach]

not stale

[levimm]

I also met this issue. When I clear snapshot, I just want to clear the dynamic resources but keep those watches.