Clarify empty state messages for `*AndWait`

[nfx]

The default could be something like "empty response", as the current status is already included in the status message. The error below will become failed to reach <dst state>, got <cur state>: empty response, instead of failed to reach <dst state>, got <cur state>: current_status: <cur state>.

Originally posted by @pietern in https://github.com/databricks/databricks-sdk-go/pull/210#discussion_r1034690443