Fix misattributed code_owner that should be arch-bom

[robrap]

[Original ticket: https://2u-internal.atlassian.net/browse/ARCHBOM-1225]

Arch-BOM no longer owns user_authn. However, it does make sense for Arch-BOM to continue to own cookies.py and the login_refresh view that serves as the backend to the cross-MFE platform code for refreshing JWT cookies.

• One way to correct the code_owner for the above code, would be moved to an Arch-BOM owned Django app.
  • However, splitting in this way may not make sense for edx-platform, unless there is a strong reason to put this code with other code?
• A better way might be to have a way to override this tagging in other ways than apps, if we are refactoring and writing our own code_owner plugin code. T
• Anything we do here should probably be blocked on DEPR and move code owner monitoring code with updates #784
• Here is a DD search for some of the traces that have a problem.
  • These are currently going to Infinity. Another solution would simply to have Infinity own this, or just be responsible for on-call.