This condition is not yet available in JWT Cloud, but you can implement it easily using the Jira expression condition.
As described in A general note about JWT for Jira Cloud, it is not possible to use the JWT field codes in conditions or validators.
Create a Jira expression condition
Enter the expression
!user.getProjectRoles(new Project(issue.project.id)).map(p => p.name).includes("PROJECT_ROLE")
where PROJECT_ROLE is the project role that the current user must not be a member of.
