Enable Duo Chat tools in self-hosted models feature settings page

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/173008



Merged-by: Eduardo Bonet <ebonet@gitlab.com>
Approved-by: Eduardo Bonet <ebonet@gitlab.com>
Reviewed-by: Eduardo Bonet <ebonet@gitlab.com>
Reviewed-by: Patrick Cyiza <jpcyiza@gitlab.com>
Co-authored-by: Julie Huang <julhuang@gitlab.com>
Co-authored-by: Patrick Cyiza <jpcyiza@gitlab.com>