[ECS] Populate Zone ID in Task Metadata

### Summary

I would like to have the [EC2 Zone ID](https://docs.aws.amazon.com/ram/latest/userguide/working-with-az-ids.html) available from task metadata

### Description

While it's great that I can now query for the availability zone from ask metadata, my company deploys across many accounts and for regions where AZ order was randomized, the AZ presented to one account may not be the same as the one in another. AWS added Zone IDs to provide a consistent identifier across accounts, and having access to this from task metadata would allow us to populate this identifier in our logs and some metrics.

### Expected Behavior

Task Metadata would additionally return a "ZoneId" field that would include the Zone ID for the corresponding AvailabilityZone field.

### Observed Behavior

N/A

### Environment Details

### Supporting Log Snippets

Start by reviewing the ECS task metadata documentation and the existing AvailabilityZone field described in the issue; no repository file or test is named. Confirm how the corresponding EC2 Zone ID should be exposed as ZoneId, then document or test the expected metadata response when the work is complete.

Written by the indexing model from the issue text.