This is the client-side error handling for when a user tries to create a role with the same name as an existing role in the community. `keyserver` support for this is added in D8432 by creating a
unique key, but we want to ideally prevent the user from getting to a point where a duplicate role name is sent to the `keyserver` and an error is thrown.
Here, when the 'Create' button is clicked, we check the role names in the current `threadInfo`, and if the same role name exists, we use the `ActionResultModal` to indicate why this role name cannot be used.
Using `ActionResultModal` was discussed in [[ https://linear.app/comm/issue/DES-44#comment-53d9d2e2 | DES-44 ]].
Part of [[ https://linear.app/comm/issue/ENG-4178/support-loadingerror-states-when-creating-a-role | ENG-4178 ]].
Depends on D8432