Warn when underscores in Snowflake account names are replaced with hyphens

[nishan-soni]

resolves #1467

Problem

This PR adds a warning when underscores (_) in the Snowflake account field are automatically replaced with hyphens (-) to form a valid account URL. Previously, this normalization happened silently, which could make debugging connection failures difficult.

Solution

Emit an AdapterEventWarning if any underscores in the account name were substituted.

Testing

Manual tests to confirm the warning was logged.

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

[colin-rogers-dbt]

If someone has set their project to error on warnings we could cause their project to unexpectedly fail. If the purpose is to make it easier to debug could we just emit a debug log instead?

[nishan-soni]

If someone has set their project to error on warnings we could cause their project to unexpectedly fail. If the purpose is to make it easier to debug could we just emit a debug log instead?

I can switch this to a debug log 👍

[colin-rogers-dbt]

Thanks, appreciate the change