For views that contain a search in their definition ($search / $vectorSearch):

• You can run an aggregation query against it that does not contain a search 
• You cannot run an aggregation query against it that contains a search (no searching on a view that has a search)

This means for $rankFusion, we should be able to run the stage with input pipelines that do not contain any searches, on a view that has a search in the definition. Like

view: [{$search/$vectorSearch}, ...]
query:
[
  $rankFusion: {
    pipelines: { // no search stages in any input pipelines
      p1: [{$match}, ..., {$sort}],
      p2: [{$geoNear}, ...]
    }
  }

We do not have tests for this, so add them to our js suite. If it turns out for some reason we cannot properly execute these queries, either fix the server code in this ticket, or file follow up ticket(s) if its more complex.

Do not worry about the cases where we are running a $rankFusion with search input pipelines against a view that has a search in it. These queries should fail and are not covered in this ticket