[FE] Add dormant member Group setting
# Background In https://gitlab.com/groups/gitlab-org/-/epics/7533+ we intend to add a feature to identify and remove dormant users from Namespaces for GitLab.com This is similar to the existing SM feature ( https://gitlab.com/groups/gitlab-org/-/epics/5519), but rather than deactivating users, we will remove members. To achieve this, we will be adding a way to track member’s last activity timestamp within a namespace, so that we can identify dormant members and remove them if they've been dormant for greater than a predefined time period (e.g. 90 days). # Purpose The purpose of this issue is to: **Add frontend form changes for updating group setting** The backend changes will be handled in: - https://gitlab.com/gitlab-org/gitlab/-/issues/461334+ - https://gitlab.com/gitlab-org/gitlab/-/issues/461335+ We can develop this behind a feature flag before the related work is complete ## Implementation * Backend: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/153099+ * Frontend: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/153118+
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