Follow-up: Change approval settings from a success alert to a success toast
As per !66536 (comment 640849831) it was identified that Pajamas recommends we use a success toast and an error alert rather than alerts for both success and error.
As the approval settings spans both groups and projects, this change has been put into this issue instead.
Implementation plan
frontend -
- Replace http://gitlab.com/gitlab-org/gitlab/blob/master/ee/app/assets/javascripts/approvals/components/approval_settings.vue#L104 with a GlToast
- Update spec tests