[ECS] [request]: Pre-populate ECS ServiceConnect timeout values while updating an ECS Service on the dashboard

### Community Note

* Please vote on this issue by adding a 👍 [reaction](https://blog.github.com/2016-03-10-add-reactions-to-pull-requests-issues-and-comments/) to the original issue to help the community and maintainers prioritize this request
* Please do not leave "+1" or "me too" comments, they generate extra noise for issue followers and do not help prioritize the request
* If you are interested in working on this issue or have submitted a pull request, please leave a comment

**Tell us about your request**
Could you pre-populate the timeout values of ECS ServiceConnect with the current values?

**Which service(s) is this request for?**
ECS ServiceConnect

**Tell us about the problem you're trying to solve. What are you trying to do, and why is it hard?**
Each time I manually update an ECS service with ServiceConnect using AWS Dashboard, I realize that ServiceConnect timeout values are not fetched and populated (I can see the current values on Cloud Map), so if I forget to populate them manually, it resets back to the default values.

**Are you currently working around this issue?**
How are you currently solving this problem?
I manually set them each time I update the service using the dashboard

**Additional context**
Anything else we should know?

**Attachments**
If you think you might have additional information that you'd like to include via an attachment, please do - we'll take a look. (Remember to remove any personally-identifiable information.)

No repository files, tests, or implementation entry points are identified. Start by reviewing the ECS ServiceConnect update flow in the AWS Dashboard and the current timeout values in Cloud Map; done means existing timeout values are fetched and pre-populated when updating an ECS service, rather than reset to defaults.

Written by the indexing model from the issue text.