Disable gitlab-experiment deprecation warnings to reduce logging volume

What does this MR do and why?

Disables deprecation notices for gitlab-experiment gem in all circumstances in an attempt to reduce the surge in logging events.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Relates to gitlab-com/gl-infra/production#6278 (closed)