Short-circuit when insert values are empty

[slvrtrn]

Summary

• If InsertParams.values is an empty array, no request is sent to the server, and ClickHouseClient.insert short-circuits itself. In this scenario, the newly added InsertResult.executed flag will be false, and InsertResult.query_id will be an empty string.

• Client no longer produces Code: 354. inflate failed: buffer error exception if request compression is enabled and InsertParams.values is an empty array (see above).

Checklist

Delete items not relevant to your PR:

• Unit and integration tests covering the common scenarios were added
• A human-readable description of the changes was provided to include in CHANGELOG