Merge branch '412384-disabling-model-experiments-in-packages-and-registries-2' into 'master'

Adds frontend to toggle visibility of model experiments

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/121653



Merged-by: Lukas 'Eipi' Eipert <leipert@gitlab.com>
Approved-by: Thomas Hutterer <thutterer@gitlab.com>
Approved-by: Michael Le <mle@gitlab.com>
Approved-by: Lukas 'Eipi' Eipert <leipert@gitlab.com>
Approved-by: Rudy Crespo <rcrespo@gitlab.com>
Reviewed-by: Lukas 'Eipi' Eipert <leipert@gitlab.com>
Reviewed-by: Eduardo Bonet <ebonet@gitlab.com>
Co-authored-by: Eduardo Bonet <ebonet@gitlab.com>