bug#63384: x-display-mm-width and x-display-mm-height both return 0 on wayland

["William A Cadegan-Schlieper" <wacs@covering.space>]

I have run into this problem and can confirm that a 0mm×0mm display is reported by Wayland in many cases, including the Weston run by the virtualized server of the WSL system.

interface: 'wl_compositor',                              version:  4, name:  1
interface: 'wl_subcompositor',                           version:  1, name:  2
interface: 'wp_viewporter',                              version:  1, name:  3
interface: 'zxdg_output_manager_v1',                     version:  2, name:  4
        xdg_output_v1
                output: 11
                name: 'rdp-0'
                logical_x: 0, logical_y: 0
                logical_width: 1920, logical_height: 1080
interface: 'wp_presentation',                            version:  1, name:  5
        presentation clock id: 4 (CLOCK_MONOTONIC_RAW)
interface: 'zwp_relative_pointer_manager_v1',            version:  1, name:  6
interface: 'zwp_pointer_constraints_v1',                 version:  1, name:  7
interface: 'zwp_input_timestamps_manager_v1',            version:  1, name:  8
interface: 'wl_data_device_manager',                     version:  3, name:  9
interface: 'wl_shm',                                     version:  1, name: 10
        formats (fourcc):
        0x36314752 = 'RG16'
                 1 = 'XR24'
                 0 = 'AR24'
interface: 'wl_output',                                  version:  3, name: 11
        x: 0, y: 0, scale: 1,
        physical_width: 0 mm, physical_height: 0 mm,
        make: 'weston', model: 'rdp',
        subpixel_orientation: unknown, output_transform: normal,
        mode:
                width: 1920 px, height: 1080 px, refresh: 60.000 Hz,
                flags: current preferred
interface: 'zwp_input_panel_v1',                         version:  1, name: 12
interface: 'zwp_text_input_manager_v1',                  version:  1, name: 13
interface: 'xdg_wm_base',                                version:  1, name: 14
interface: 'zxdg_shell_v6',                              version:  1, name: 15
interface: 'wl_shell',                                   version:  1, name: 16
interface: 'weston_rdprail_shell',                       version:  1, name: 17
interface: 'weston_screenshooter',                       version:  1, name: 18
interface: 'wl_seat',                                    version:  7, name: 19
        name: RDP DESKTOP-QGUMTJ2
        capabilities: pointer keyboard
        keyboard repeat rate: 40
        keyboard repeat delay: 400
interface: 'zwp_input_method_v1',                        version:  1, name: 20