[Bug] Remove private_key_path from SnowflakeCredentials._connection_keys

[jtcohen6]

Is this a new bug in dbt-snowflake?

• I believe this is a new bug in dbt-snowflake
• I have searched the existing issues, and I could not find an existing issue for this bug

Current Behavior

follow-up to #906 + #756

internal Slack thread

private_key_path is included in SnowflakeCredentials._connection_keys, and therefore the Jinja {{ target }} dictionary. While this value doesn't explicitly contain sensitive information itself, I'd put it in the category of password-like fields rather than the category of fields that a user needs to access at runtime.

Expected Behavior

private_key_path is not included in _connection_keys

Steps To Reproduce

n/a

Relevant log output

No response

Environment

- dbt-core: 1.7.10
- dbt-snowflake: 1.7.2

Additional Context

internal thread