feat(clustering/rpc): update dp status after syncing

[chronolaw]

Summary

KAG-6223

Checklist

• The Pull Request has tests
• A changelog file has been created under changelog/unreleased/kong or skip-changelog label added on PR if changelog is unnecessary. README.md
• There is a user-facing docs PR against https://github.com/Kong/docs.konghq.com - PUT DOCS PR HERE

Issue reference

Fix #[issue number]

[StarlightIbuki]

The solution should work. An improvement is possible

[StarlightIbuki]

We could start a timer to call the notification here as it ignores the response , so to release the lock quicker

[chronolaw]

The rpc notification is very cheap, I think that we need not to run a new timer here.

[chobits]

i checked the inside logic of notify, there's no block logic, at last, it will call msg push, is it right ? so i think we do not need to introduce a timer

final logic of notify()

notify
-> fut.start
  -> socket: call
    -> 
-- asynchronously start executing a RPC, _node_id is not
-- needed for this implementation, but it is important
-- for concentrator socket, so we include it just to keep
-- the signature consistent
function _M:call(node_id, method, params, callback)
  assert(node_id == self.node_id)

  local id

  -- notification has no callback or id
  if callback then
    id = self:_get_next_id()
    self.interest[id] = callback
  end

  return self:push_request({
    jsonrpc = jsonrpc.VERSION,
    method = method,
    params = params,
    id = id,
  })
end

[StarlightIbuki]

@chronolaw @ADD-SP Let's move this PR forward and after merging this we can close #14194

[chronolaw]

Cherry-pick is blocked by #14195 .