Worker quarantine time not displayed properly

[nthomas-mozilla]

I quarantined a worker until 3019 but the UI shows "Quarantine until 11"

To Reproduce

1. Go to the mac-v3-signing8 worker page
2. Look at the Quarantine Until value

Alternatively, find a worker to quarantine and accept the default value of now + 1000 years.

Expected behavior
Probably a humanized date like 3019, or 'for 4 days', with a tooltip giving the full timestamp (similar to run start/completed).

Screenshots

Platform (please complete the following information):

• Firefox TC instance
• Mac Firefox 71.0b8