Fix --debug-xr not outputting OpenXR debug prints on Windows

The OpenXR debug extension was disabled on Windows as a workaround. This
was an old leftover from when there was only the Windows Mixed Reality
runtime on Windows. The debug extension didn't work for it and we didn't
have a way to disable it just for Windows Mixed Reality.
Now it seems to work though, so we remove the workaround. If specific
runtimes still have trouble with the extension, we can disable it
specifically for these runtimes now.

intern/ghost/intern/GHOST_XrContext.cpp

@@ -408,11 +408,9 @@ void GHOST_XrContext::getExtensionsToEnable(
   std::vector<std::string> try_ext;
 
   /* Try enabling debug extension. */
-#ifndef WIN32
   if (isDebugMode()) {
     try_ext.push_back(XR_EXT_DEBUG_UTILS_EXTENSION_NAME);
   }
-#endif
 
   r_ext_names.reserve(try_ext.size() + graphics_binding_types.size());