hello_xr vulkan backend ignores `minApiVersion` from graphics requirements structs

[fredemmott]

VK 1.0 is hardcoded here:

OpenXR-SDK-Source/src/tests/hello_xr/graphicsplugin_vulkan.cpp

Line 1386 in 820278f

appInfo.apiVersion = VK_API_VERSION_1_0;

For XR_KHR_vulkan_enable2, the version can (should) be forced by the runtime or an API layer's implementation of xrCreateVulkanInstanceKHR, however this isn't supported via XR_KHR_vulkan_enable - for the older OpenXR extension, the app should respect the min api version from XrGraphicsRequirementsVulkanKHR and use it for vkCreateInstance()

[rpavlik-bot]

An issue (number 2208) has been filed to correspond to this issue in the internal Khronos GitLab (Khronos members only: KHR:openxr/openxr#2208 ), to facilitate working group processes.

This GitHub issue will continue to be the main site of discussion.