Current default G_MAXINT is not a correct value under any circumstances. This creates an issue with screen capture, during which we currently do not get any framerate info causing G_MAXINT to show up, where elements downstream can possibly misbehave - for example, `vtenc` causes a kernel panic. Replace with 30/1 to avoid such scenarios. Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/2944>