[BUGFIX] Set application query param for SnowflakeDatasource

[roblim]

• Set application query param for SnowflakeDatasource when creating engine. This is to ensure GX gets attribution for the Snowflake Partner program

• This was attempted previously by setting the SF_PARTNER env var, which would typically be picked up by the Snowflake connecter to set the application query param. However, since GX uses snowflake-sqlalchemy to connect to Snowflake, the env var gets superseded, with attribution going to snowflake-sqlalchemy.

• [x] PR title is prefixed with one of: [BUGFIX], [FEATURE], [DOCS], [MAINTENANCE], [CONTRIB]

• [x] Code is linted - run invoke lint (uses ruff format + ruff check)

• [x] Appropriate tests and docs have been updated

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