Add error handling in updateTaskList to reduce constant logging of 403s

[marcellamaki]

Description of the change(s) you made

Fixes #3291

Adds two conditions to manage 403 errors -- one when the router is available, and one when it is not

Manual verification steps performed/Reviewer guidance

1. Sign in and open 2 tabs in studio
2. Navigate to the channel editor
3. Sign out in one tab
4. The other tab should sign out and redirect to the login screen also (it might be a slight lag) and neither console should register any 403 errors

Are there any risky areas that deserve extra testing?

Any conditions I have missed?

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Reviewer's Checklist

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• Automated test coverage is satisfactory
• PR is fully functional
• PR has been tested for accessibility regressions
• External dependency files were updated if necessary (yarn and pip)
• Documentation is updated
• Contributor is in AUTHORS.md