Log ClientDenied events as Debug

[rhysparry]

Background

The client denied error messages can create a lot of noise in the logs.

Results

Client denied events will be logged as Debug level events.

Resolves #598

How to review this PR

Quality :heavy_check_mark:

Pre-requisites

• [x] I have read How we use GitHub Issues for help deciding when and where it's appropriate to make an issue.
• [x] I have considered informing or consulting the right people, according to the ownership map.
• [x] I have considered appropriate testing for my change.

[shortcut-integration[bot]]

This pull request has been linked to Shortcut Story #73056: Review Halibut logging for attempted connections by unauthorized polling Tentacles.