isOlderThanOrEqual1_15_2

Offhand cannot be used as a SWAP target in any container on 1.15.2 and below.

https://github.com/ViaVersion/ViaFabricPlus/blob/8f96c699edc97db8a3fc58c1533e8cf41dd46aaf/src/main/java/com/viaversion/viafabricplus/injection/mixin/features/v1_15_2/MixinMultiPlayerGameMode.java#L67