Fix g3.xl flavor information
On https://docs.jetstream-cloud.org/general/instance-flavors/#jetstream2-gpu we need to change g3.xl RAM to 120gb to reflect an operational change we needed to make for whole/multi-card flavors
On https://docs.jetstream-cloud.org/general/instance-flavors/#jetstream2-gpu we need to change g3.xl RAM to 120gb to reflect an operational change we needed to make for whole/multi-card flavors