Always On Top: Dedup the alwaysontop command id in window system menu (#45845)

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fix/what does it change/how was it tested (even manually, if necessary)?
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## Summary of the Pull Request
We picked a command id for always on top, although it has little
possibility, but may collide with other window system menu item, so
before inject, try to see if it persists, if yes, then we don't inject.


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## PR Checklist

- [ ] Closes: #xxx
<!-- - [ ] Closes: #yyy (add separate lines for additional resolved
issues) -->
- [ ] **Communication:** I've discussed this with core contributors
already. If the work hasn't been agreed, this work might be rejected
- [ ] **Tests:** Added/updated and all pass
- [ ] **Localization:** All end-user-facing strings can be localized
- [ ] **Dev docs:** Added/updated
- [ ] **New binaries:** Added on the required places
- [ ] [JSON for
signing](https://github.com/microsoft/PowerToys/blob/main/.pipelines/ESRPSigning_core.json)
for new binaries
- [ ] [WXS for
installer](https://github.com/microsoft/PowerToys/blob/main/installer/PowerToysSetup/Product.wxs)
for new binaries and localization folder
- [ ] [YML for CI
pipeline](https://github.com/microsoft/PowerToys/blob/main/.pipelines/ci/templates/build-powertoys-steps.yml)
for new test projects
- [ ] [YML for signed
pipeline](https://github.com/microsoft/PowerToys/blob/main/.pipelines/release.yml)
- [ ] **Documentation updated:** If checked, please file a pull request
on [our docs
repo](https://github.com/MicrosoftDocs/windows-uwp/tree/docs/hub/powertoys)
and link it here: #xxx

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## Detailed Description of the Pull Request / Additional comments

<!-- Describe how you validated the behavior. Add automated tests
wherever possible, but list manual validation steps taken as well -->
## Validation Steps Performed
A window with the same id
<img width="1049" height="301" alt="image"
src="https://github.com/user-attachments/assets/ae0ba9b7-c46c-4cbf-8994-e0dc4e5c3527"
/>

You can see there is no always ontop overriding the test item

Normal window:
<img width="468" height="597" alt="image"
src="https://github.com/user-attachments/assets/2ba034a8-c41e-4233-9435-4323c8f1c7a4"
/>