Add snowflake telemetry.

[VersusFacit]

Related to dbt-labs/dbt-adapters#301

Problem

We need a snowflake override to get the data for snowflake.

Solution

Override the base class method.

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

[VersusFacit]

Note my base adapter was 1.7.X so we have the overrides right!

And it's the core tracking function that is using the Snowflake override :D

My local env for testing.

[mikealfare]

Besides the one question, is it worth adding a test to this since we are tracking an additional dbt-snowflake-specific attribute?

[VersusFacit]

I suppose it's worth adding a unit test (done) because this gives us extra security with base adapter / core calls that could be tripped up through many layers of indirection.