[Settings] Optimizing and cleaning up code (#44721)

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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

- Removing dead experiments code
- Refactoring and simplifying OOBE/SCOOBE windowing code
- Removing dead assets
- Optimizing CmdPal assets to lower res shaving off a few MBs
- Scrolling works better on the What's new page
- Should be merged after: #44638

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## PR Checklist

- [X] Closes: #44958
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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

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---------

Co-authored-by: Gordon Lam (SH) <yeelam@microsoft.com>

PowerToys.slnx

@@ -4,10 +4,6 @@
     <Platform Name="x64" />
   </Configurations>
   <Folder Name="/common/">
-    <Project Path="src/common/AllExperiments/AllExperiments.csproj">
-      <Platform Solution="*|ARM64" Project="ARM64" />
-      <Platform Solution="*|x64" Project="x64" />
-    </Project>
     <Project Path="src/common/CalculatorEngineCommon/CalculatorEngineCommon.vcxproj" Id="2cf78cf7-8feb-4be1-9591-55fa25b48fc6" />
     <Project Path="src/common/Common.Search/Common.Search.csproj">
       <Platform Solution="*|ARM64" Project="ARM64" />