feat(ec2): support throughput on LaunchTemplate EBS volumes

[isker]

Issue # (if applicable)

Fixes #24341.

Reason for this change

You currently can't specify throughput on LaunchTemplate EBS volumes.

Description of changes

This support was simply not included in ec2 when it was added to autoscaling in #22441. I have copied that PR's implementation implementation to ec2 and similarly adapted its tests.

Description of how you validated changes

Unit and integration tests.

Checklist

• [x] My code adheres to the CONTRIBUTING GUIDE and DESIGN GUIDELINES

---

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license