bugfix: improve shutdown and stop PoA sooner (#3289)

## Linked Issues/PRs
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## Description
<!-- List of detailed changes -->

Because the services were being being shutdown in the same order they
were started, the PoA service can be held up by earlier services. This
means that our producers could be nominally "shut down" but the PoA
service still runs a while. The old leader would still hold on to its
lock, but it wouldn't be broadcasting blocks anymore.

The solution here is to shutdown all of the services in parallel, this
way none of them is blocking the others.

The other part of the PR is taking care of the GraphQL which was the
culprit for PoA never being shut down. We've added a timeout to force it
to shutdown if it doesn't shut down gracefully.

## Checklist
- [ ] Breaking changes are clearly marked as such in the PR description
and changelog
- [ ] New behavior is reflected in tests
- [ ] [The specification](https://github.com/FuelLabs/fuel-specs/)
matches the implemented behavior (link update PR if changes are needed)

### Before requesting review
- [ ] I have reviewed the code myself
- [ ] I have created follow-up issues caused by this PR and linked them
here

### After merging, notify other teams

[Add or remove entries as needed]

- [ ] [Rust SDK](https://github.com/FuelLabs/fuels-rs/)
- [ ] [Sway compiler](https://github.com/FuelLabs/sway/)
- [ ] [Platform
documentation](https://github.com/FuelLabs/devrel-requests/issues/new?assignees=&labels=new+request&projects=&template=NEW-REQUEST.yml&title=%5BRequest%5D%3A+)
(for out-of-organization contributors, the person merging the PR will do
this)
- [ ] Someone else?

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Co-authored-by: xgreenx <xgreenx9999@gmail.com>
Co-authored-by: Claude Opus 4.7 <noreply@anthropic.com>