Create CTA for users to try out new reference panel

Created by: jjinnii

We would like to collect external feedback on our new reference panel at the same time that we've enabled it for internal dogfooding. Instead of a controlled user test, we will try out a CTA to try out a beta experience of the reference panel and collect feedback. cc: @macraig @rrhyne

• Create a new (or clean up) existing issue #30227 (closed) for external use. It should include instructions for set up, as well as instructions to provide feedback directly into the issue
• Create alert inside reference panel that links to the external-facing issue for reference panel
• Metrics: Can we track the count of non-sourcegraph-teammate users who have enabled the feature flag? Or would we have to track count of clicks on the CTA?