If AV1 is unsupported by server, the negociation between the server and Moonlight results in H264 codec instead of HEVC if available

[henryfa2]

If AV1 is unsupported by server, the negociation between the server and Moonlight results in H264 codec instead of HEVC if available. At the moment, the user gotta select manually HEVC in Moonlight instead of AV1 if his computer do not handle AV1 encoding (which starts with Geforce 4000 series). I'm gonna try to correct that later