195788 - add ECS instance profile service to elastic search client

What does this MR do?

This MR fixes issue #195788 (closed) by adding the ECS instance metadata credentials to the AWS credential resolver.

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Separation of EE specific content

Availability and Testing

The risks of doing this change are AWS credentials for elasticsearc stop working. This has been mitigated as part of testing that I have done on my own EC2 and ECS clusters.

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• [-] Tested in all supported browsers
• [-] Informed Infrastructure department of a default or new setting change, if applicable per definition of done