SPIKE: allow user to authenticate for the Hypothesis Reporting Dashboard if the cookie has expired

[mkdir-washington-edu]

Slack thread: https://hypothes-is.slack.com/archives/C4K6M7P5E/p1732197016041389

The issue:
We've tried to strike a balance between security and convenience with a 1-week long cookie duration. For users who are still getting logged out, we want to direct them to the correct place to authenticate (or, ideally, present them with a way of authenticating on the spot).

Next steps:
Investigate the options, for each LMS we service, for allowing users who have lost access to the reporting dashboards to re-authenticate in as clear and simple a way as possible.