[Find My Mouse] Adding transparency support for spotlight (#41701)

<!-- Enter a brief description/summary of your PR here. What does it
fix/what does it change/how was it tested (even manually, if necessary)?
-->
## Summary of the Pull Request
### Feature
Separate the find my mouse's spotlight area with the backdrop, so that
we could support the frequent ask - We should leave the circle
transparent in find my mouse

### Engineering:
1. Modernize the framework - From UWP composition to WASDK composition
api

<!-- Please review the items on the PR checklist before submitting-->
## PR Checklist

- [x] Closes: #15512
- [ ] **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

<!-- Provide a more detailed description of the PR, other things fixed,
or any additional comments/features here -->
## 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
- [x] Data migration: Should nota break existing experience when upgrade
- [x] Should be able to configure the background and spotlight opacity 
- [x] Should be able to work with different settings


https://github.com/user-attachments/assets/6f311c03-fa79-41d3-94bb-589d853295f4

---------

Co-authored-by: Niels Laute <niels.laute@live.nl>

.github/actions/spell-check/expect.txt

@@ -918,6 +918,7 @@ LWA
 lwin
 LZero
 MAGTRANSFORM
+MAJORMINOR
 MAKEINTRESOURCE
 MAKEINTRESOURCEA
 MAKEINTRESOURCEW
@@ -996,6 +997,9 @@ mousepointercrosshairs
 mouseutils
 MOVESIZEEND
 MOVESIZESTART
+muxx
+muxxc
+muxxh
 MRM
 MRT
 mru
@@ -1807,6 +1811,7 @@ ULONGLONG
 ums
 uncompilable
 UNCPRIORITY
+undefining
 UNDNAME
 UNICODETEXT
 unins