c/main: Add bigscreen beyond to NV whitelist

Part-of: <https://gitlab.freedesktop.org/monado/monado/-/merge_requests/2550>

src/xrt/compositor/main/comp_settings.h

···
     "Valve Corporation Index HMD", // Valve Index
     "Seiko/Epson SEC144A",         // Samsung Odyssey+
     "HPN",                         // Reverb G2
+    "Bigscreen, Inc. Beyond",      // Bigscreen Beyond
     "PNP",                         // NorthStar (Generic)
 };