[CmdPal][AOT] Make fileSearch ext become AOT compatible (#39732)

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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
* Use source generation to replace some csWin32 function call.
* Clean up some AOT compatible issues.

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## PR Checklist

- [x] **Closes:** #39889
- [x] **Communication:** I've discussed this with core contributors
already. If work hasn't been agreed, this work might be rejected
- [x] **Tests:** Added/updated and all pass
- [x] **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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or any additional comments/features here -->
## Detailed Description of the Pull Request / Additional comments

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wherever possible, but list manual validation steps taken as well -->
## Validation Steps Performed

If you want to try it out, please see
https://github.com/microsoft/PowerToys/pull/39605

---------

Co-authored-by: Yu Leng <yuleng@microsoft.com>

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

@@ -1995,4 +1995,15 @@ culori
 Evercoder
 LCh
 CIELCh
-CLSCTXINPROCALL
+CLSCTXINPROCALL
+IIDI
+irow
+lcid
+OTHERUNZOOM
+OTHERZOOM
+PARENTCLOSING
+PARENTOPENING
+ppwsz
+rguid
+SCROLLCHILDREN
+VARTYPE