Merge branch 'escalation-empty-state' into 'master'

Update Escalation Policies empty state illustration

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/167497



Merged-by: Frédéric Caplette <fcaplette@gitlab.com>
Approved-by: Chad Lavimoniere <clavimoniere@gitlab.com>
Approved-by: Kev Kloss <kkloss@gitlab.com>
Approved-by: Roy Zwambag <rzwambag@gitlab.com>
Approved-by: Frédéric Caplette <fcaplette@gitlab.com>
Co-authored-by: Julia Miocene <jmiocene@gitlab.com>