Update Role Targeting in Broadcast Messages

Summary

The recent clean up of FF role_targeted_broadcast_messages introduced non-intuitive behaviour to Broadcast Messages targeting.

Specifically that if you select a Role to target, this impacts where a broadcast message is displayed. This is not intuitive to anyone creating a broadcast message.

Previous Behaviour

Before the role change - a Broadcast Message would show when not under a group or project like on https://gitlab.com/

Current Behaviour

After the role change - a Broadcast Message will only show when you go under a group or project if you've selected a Role to target

Because Roles are associated with access to a group/project, the introduction of targeting by roles inadvertently also introduced group/project level visibility of broadcast messages.

Proposed changes

• Use progressive disclosure only to show the extra form fields when the radio option is selected.
  • This reduces the initial cognitive load of seeing the entire form when loaded on the page.
• Add 'Target broadcast message' to the form

Default view

Target broadcast message
(x) Show to all users on all pages
( ) Show to all users on specific matching pages
( ) Show only on groups/project pages

Scenario: All users page matching a pattern

Target broadcast message
( ) Show to all users on all pages
(x) Show to all users on specific matching pages
    Target path: [<pattern>]
( ) Show only on groups/project pages

Scenario: Only developers and maintainers on pages matching a path in group/project pages

Target broadcast message
( ) Show to all users on all pages
( ) Show to all users on specific matching pages
(x) Show only on groups/project pages
    ( ) All members
    (x) Only to members with specific roles
        [ ] Guest
        [ ] Reporter
        [x] Developer
        [x] Maintainer
        [ ] Owner

    Pages to target
    ( ) All pages
    (x) Specific matching pages
        Target path: [<pattern>]