Fix adapter selection in Vulkan demo

[SCLDGit]

Changed the adapter index in the for loop to correctly iterate through available adapters. This ensures that the correct adapter is selected based on its Luid.

What does the pull request do?

This request fixes an index error in D3DMemoryHelper.cs that prevented usage of any graphics adapters other than the one in slot 0.

What is the current behavior?

factory.GetAdapter1() was hard-coded to always use index zero when iterating through graphics devices

What is the updated/expected behavior with this PR?

factory.GetAdapter1() now properly uses the iterator index when iterating through graphics devices

How was the solution implemented (if it's not obvious)?

Changed hard-coded '0' value to the index variable.

Checklist

• [ ] Added unit tests (if possible)?
• [ ] Added XML documentation to any related classes?
• [ ] Consider submitting a PR to https://github.com/AvaloniaUI/avalonia-docs with user documentation

Breaking changes

Obsoletions / Deprecations

Fixed issues

[avaloniaui-bot]

You can test this PR using the following package version. 11.3.999-cibuild0053108-alpha. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]

[cla-avalonia]

• [x] All contributors have signed the CLA.

[SCLDGit]

@cla-avalonia agree