This is the client-side implementation of allowing a user to save their custom role for their community. Since CreateRolesHeaderRightButton needs access to both the roleName and the rolePermissions, it made sense to include those in the navigation route params, and I can pull them directly from there. That's why the React.useEffect hook updates the params.
This is also useful because once I work on the edit_role flow, I can default the roleName and rolePermissions to the existing name/permissions to 'pre-fill' the info for the client.
Depends on D8420