OperationShape::NAME as ShapeId (#2678) (#2717)

See https://github.com/awslabs/smithy-rs/issues/2634



## Checklist
<!--- If a checkbox below is not applicable, then please DELETE it
rather than leaving it unchecked -->
- [x] I have updated `CHANGELOG.next.toml` if I made changes to the
smithy-rs codegen or runtime crates
- [ ] I have updated `CHANGELOG.next.toml` if I made changes to the AWS
SDK, generated SDK code, or SDK runtime crates

----

_By submitting this pull request, I confirm that you can use, modify,
copy, and redistribute this contribution, under the terms of your
choice._

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Signed-off-by: Daniele Ahmed <ahmeddan@amazon.de>
Co-authored-by: Harry Barber <106155934+hlbarber@users.noreply.github.com>