Mark ai_access_token as ignored correctly

What does this MR do and why?

This MR marks the ai_access_token as ignored correctly. Previously it did not have the encrypted_ prefix.

This is part of the Corrective action: https://gitlab.com/gitlab-com/gl-infra/reliability/-/issues/24523

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.

Related to: #427694 (closed)

Corrective action issue: https://gitlab.com/gitlab-com/gl-infra/reliability/-/issues/24523#top