Avoid modesets if possible

[YaLTeR]

Modesets can sometimes be avoided if the connector already has the mode that we want it to have. However, this needs to be very carefully implemented and tested since failing to light up a monitor in some cases is much worse than having extra modesets.

Relevant code from cosmic-comp: https://github.com/pop-os/cosmic-comp/blob/e569e14a99c6471dd7b9536d795448f2a8c8c948/src/backend/kms/drm_helpers.rs#L14