hello_xr: Command line option for hello_xr not actually supported

[TheFakeMontyOnTheRun]

One of the command line options for hello_xr is:

View configurations:      Mono, Stereo

But as far as I could verify, the option is not actually supported, as the line 598 of openxr_program.cpp is:

        // Note: No other view configurations exist at the time this code was written. If this
        // condition is not met, the project will need to be audited to see how support should be
        // added.
        CHECK_MSG(m_options->Parsed.ViewConfigType == XR_VIEW_CONFIGURATION_TYPE_PRIMARY_STEREO,
                  "Unsupported view configuration type");

Should this option be removed from the list of options?
If so, I'll gladly provide a PR to do it.

[rpavlik-bot]

An issue (number 2679) has been filed to correspond to this issue in the internal Khronos GitLab (Khronos members only: KHR:openxr/openxr#2679 ), to facilitate working group processes.

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

[TheFakeMontyOnTheRun]

I notice now that the issue very badly describes the situation: Mono is not supported.