Add Snowflake session id to run result

[jeppe742]

resolves #881

Problem

As described in #881, it would be very useful to get the session_id from the RunResult.
This especially makes sense for incremental models, where the model is split into multiple queries, of which only the last is returned by query_id, but all have the same session_id

Solution

Similar to #109, we will just add a property to SnowflakeAdapterResonse and fetch the session_id from the Snowflake connection

Checklist

• I have read the contributing guide and understand what's expected of me
• I have run this code in development and it appears to resolve the stated issue
• This PR includes tests, or tests are not required/relevant for this PR
• This PR has no interface changes (e.g. macros, cli, logs, json artifacts, config files, adapter interface, etc) or this PR has already received feedback and approval from Product or DX