Allow web content media queries to be handled with OnRequestMediaAccessPermission

When getDisplayMedia is called in javascript along with the preferCurrentTab option, Chromium will do a GUM_TAB_AUDIO_CAPTURE/GUM_TAB_VIDEO_CAPTURE media query which is not implemented. Therefore, OnRequestMediaAccessPermission's requested_permissions will be CEF_MEDIA_PERMISSION_NONE and the query will receive a PERMISSION_DENIED result as per CefMediaAccessQuery#ExecuteCallback.