If you select either of the Search-related stages in the APB, an error appears reporting a connection problem with the mongot (this makes sense as the mongot will not start up unless the user configures Search).
Unfortunately, the error does not go away if you change the aggregation stage (see screenshot showing me having switched aggregation stages and the error stays). Even changing tabs does not make the error go away.
A good fix might involve making the error go away if we change the aggregation stage. An even better fix could also potentially not show the $search/$searchMeta stages for clusters that do not have Search enabled.