SNOW-1848371 adding connection.is_valid to perform connection validation on TCP/IP and Session levels

[sfc-gh-dszmolka]

Please answer these questions before submitting your pull requests. Thanks!

1. What GitHub issue is this PR addressing? Make sure that there is an accompanying issue to your PR.

   Fixes SNOW-1848371

2. Fill out the following pre-review checklist:

   • I am adding a new automated test(s) to verify correctness of my new code
   • I am adding new logging messages
   • I am adding a new telemetry message
   • I am modifying authorization mechanisms
   • I am adding new credentials
   • I am modifying OCSP code
   • I am adding a new dependency

3. Please describe how your code solves the related issue.

   The PR is for covering a gap where seemingly there's no convenience method to tell 'is this connection still good enough to send queries over it?' . See details in the jira, but basically motivated by the situation where the cloud provider LB tears down the underlying idle connection unilaterally without telling the client, who then tries the submit the next query after the idleness ends, over a socket which is already closed on the other end - ending up with an error.

Having such a mechanism which the Node.js driver already has, gives the users a tool to conveniently control if the connection/session is still valid or they need to do something about it.

Plus fixing two very minor typos.

4. (Optional) PR for stored-proc connector:

[sfc-gh-mkeller]

Deal with the small comment first, otherwise looks great. Thank you!

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