ecs-agent depends on deprecated Docker packages

It looks like the ecs-agent package has fallen behind on its depedency with `github.com/docker/docker`.

The main issue is that with v29 they've finally decided to fully switch to `github.com/moby/moby`.

The secondary issue is that a few uses have changed upstream so if you update to v28 there are missing types.

```
# github.com/aws/amazon-ecs-agent/ecs-agent/tmds/handlers/v4/state
../../../go/pkg/mod/github.com/aws/amazon-ecs-agent/ecs-agent@v0.0.0-20260421173302-3def019fc9fa/tmds/handlers/v4/state/response.go:142:9: undefined: types.StatsJSON
```

Start with the dependency declarations and ecs-agent/tmds/handlers/v4/state/response.go, especially the reference to types.StatsJSON. Check the Docker/Moby version transition and the upstream API changes, then run the relevant ecs-agent tests. Done means the agent builds without missing Docker types on the supported dependency version.

Written by the indexing model from the issue text.