[Installer] Upgrade the installer from WiX3 to WiX5 (#40877)

<!-- 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
Background: The current PowerToys installer is built using Wix3, which
has now been deprecated. To improve security, service quality, and
community support, we’re upgrading the installer to Wix5.

Implementation:
Created Wix5-based projects(PowerToysSetupVext and
PowerToysSetupCustomActionsVNext) within the installer while retaining
the existing Wix3 project. Both versions are built to generate separate
installation packages. The Wix3-related code will be removed after
successful release testing confirms no issues.

Special case:
Wix5 has removed the property for 'ShowFilesInUse'. Now, whenever a file
is in use during installation, a FilesInUse pop-upwill automatically
appear asking for the next step. To ensure this doesn't interfere with
scenarios that require silent installation (e.g. Winget method), we’ve
handled it using the bafunction approach.



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

- [ ] Closes: #xxx
- [ ] **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

---------

Co-authored-by: Jerry Xu <n.xu@outlook.com>
Co-authored-by: Kai Tao <69313318+vanzue@users.noreply.github.com>
Co-authored-by: leileizhang <leilzh@microsoft.com>
Co-authored-by: Kai Tao (from Dev Box) <kaitao@microsoft.com>
Co-authored-by: vanzue <vanzue@outlook.com>

installer/PowerToysSetupCustomActionsVNext/RcResource.h

@@ -0,0 +1,63 @@
+#pragma once
+
+#include <string_view>
+#include <optional>
+#include <filesystem>
+#include <fstream>
+
+#include <Windows.h>
+
+class RcResource
+{
+public:
+    const std::byte* _memory = nullptr;
+    size_t _size = 0;
+
+    static inline std::optional<RcResource> create(int resource_id, const std::wstring_view resource_class, const HINSTANCE handle = nullptr)
+    {
+        const HRSRC resHandle = FindResourceW(handle, MAKEINTRESOURCEW(resource_id), resource_class.data());
+        if (!resHandle)
+        {
+            return std::nullopt;
+        }
+
+        const HGLOBAL memHandle = LoadResource(handle, resHandle);
+        if (!memHandle)
+        {
+            return std::nullopt;
+        }
+
+        const size_t resSize = SizeofResource(handle, resHandle);
+        if (!resSize)
+        {
+            return std::nullopt;
+        }
+
+        auto res = static_cast<const std::byte*>(LockResource(memHandle));
+        if (!res)
+        {
+            return std::nullopt;
+        }
+
+        return RcResource{ res, resSize };
+    }
+
+    inline bool saveAsFile(const std::filesystem::path destination)
+    {
+        std::fstream installerFile{ destination, std::ios_base::binary | std::ios_base::out | std::ios_base::trunc };
+        if (!installerFile.is_open())
+        {
+            return false;
+        }
+
+        installerFile.write(reinterpret_cast<const char*>(_memory), _size);
+        return true;
+    }
+
+private:
+    RcResource() = delete;
+    RcResource(const std::byte* memory, size_t size) :
+        _memory{ memory }, _size{ size }
+    {
+    }
+};