Docker automation tweak

[emmyoop]

resolves #
docs dbt-labs/docs.getdbt.com/#

Problem

Nightly tests don't have sufficient permissions now that Docker releases have been added
Additionally, Docker released fail on a draft release since the tag does not exist.

Solution

Add the package: write permission to the nightly release
Do not release to Docker when we are running the release as a test
Allow the release to only release to Docker when a flag is flipped. This will allow us to release to Docker as needed if the final release already exists.

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

[github-actions]

Thank you for your pull request! We could not find a changelog entry for this change. For details on how to document a change, see the dbt-snowflake contributing guide.

[github-actions]

Thank you for your pull request! We could not find a changelog entry for this change. For details on how to document a change, see the dbt-snowflake contributing guide.