Fix MPP-2857 - Add logic to prompt user to login if any authentication information is missing

[maxxcrawford]

Summary

This PR addresses a possible migration issue where the profileID variable (saved in local storage) is missing. This can result in a broken/loading state in the popup. The fix here is to check if that variable is accessible during the init function. If it's missing, we prompt the user to re-login in to add it back correctly.

Fixes:

• MPP-2857
• MPP-2861
• MPP-3013

Steps to reproduce

• Run the add-on as normal, log in
  • Just in case, please close the dashboard page.
• Open about:devtools-toolbox?id=private-relay%40firefox.com&type=extension
• Run the following console command to remove the profileID from local storage
  • await browser.storage.local.remove("profileID");
• Open panel
• Expected: You should see the logged out "sign in" prompt
• Click "Sign in", and go through auth flow again
• Open panel again
• Expected: You should see mask list, etc. (Normal experience)

Screenshots

N/A