[ECS] [request]: Include the enableECSManagedTags option in the UpdateService API

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**Tell us about your request**
What do you want us to build?

Support to modify the `enableECSManagedTags` parameter on existing services via the `UpdateService` API call

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

**Tell us about the problem you're trying to solve. What are you trying to do, and why is it hard?**

At this point, the only way to enable this is during service creation.

If you would like to use Cost Explorer you need to recreate all the services that do not have ECS Managed Tasks enabled in order to see the cost allocation in the report.

This is less than ideal if some sort of IaC tool is being used in order to keep track of your services.

**Are you currently working around this issue?**
How are you currently solving this problem?

Service Deletion and Creation

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

No

**Attachments**
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