Fix DX11 shared textures

[tebjan]

Re-do of #1759 as it was lost in a force push.

PR Details

Right now creating a texture from a native texture with D3D11_RESOURCE_MISC_SHARED_NTHANDLE will fail unless it is also D3D11_RESOURCE_MISC_SHARED_KEYEDMUTEX. This combination is recomended but not mandatory acording to the specification: https://learn.microsoft.com/en-us/windows/win32/api/d3d11/ne-d3d11-d3d11_resource_misc_flag

Description

The PR changes the code that checks for shared handles from a switch/case to an if/else where the check is done for flags using a bitwise and instead of comparing the full flag to an specific value. Shared NT is checked first as Shared & SharedNT can be set at the same time.

Related Issue

#1758

Motivation and Context

Allows to use DX11 textures with an NT handle but no keyed mutex

Types of changes

• Docs change / refactoring / dependency upgrade
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• My change requires a change to the documentation.
• I have added tests to cover my changes.
• All new and existing tests passed.