Nimbus UI improvements to accomodate updated metrics metadata from Jetstream

[data-sync-user]

This is a follow-up to https://mozilla-hub.atlassian.net/browse/CIRRUS-781 for updating the UI side using new fields in the Jetstream metadata for metrics. We should be able to create a more complete display using the new status information created as part of the referenced task.

┆Issue is synchronized with this Jira Task

[data-sync-user]

➤ Mike Williams commented:

Per comment on https://mozilla-hub.atlassian.net/browse/CIRRUS-781 ( https://mozilla-hub.atlassian.net/browse/CIRRUS-781|smart-link ), when displaying each metric's statistics, it will either: a) not exist (experiment still running), b) exist (display as normal), or c) not exist and there will be an error metadata file (display helpful error message).