devel/efl: rename AV1 to AVIF after e931660117bf

OPTIONS_{,UN}SET += AVIF to globally turn on/off libavif dependency.
AV1 mainly refers to video codec which has several implementations,
so as port option name it's too ambiguous.

Originally, missed due to BROKEN before da3e12b3bafa blocking QA.

PR: 263025
Approved by: arrowd