[az] Add `zone` in the Details pane of an instance

**What are you trying to do?**
Obtain the zone associated to an instance.

**What's your proposed solution?**
Modify the Details section of an instance to display its zone.
For now, it can only be found in the All Instances page.

**Additional context**
Add any other context or screenshots about the feature request here.

Start at the instance Details pane and the All Instances page, which already exposes the zone. Trace how instance metadata reaches these views, then display the same zone in Details and verify that the value matches what is shown in All Instances.

Written by the indexing model from the issue text.