Limit the number of PathFinder paths in the Back-End

[dkoslicki]

Some pathfinder queries, such as:

{
   "nodes": {
      "n0": {
         "ids": [ "CHEBI:31690" ]
      },
      "n1": {
         "ids": [ "MONDO:0004784" ]
      }
   },
   "paths": {
      "p0": {
         "subject":   "n0",
         "object":    "n1",
         "intermediate_nodes": [],
         "predicates": [ "biolink:related_to" ]
      }
   }
}

return a paths.

Similar to how we truncate the number of results for lookup and inferred queries, we should probably limit the number of paths returned. Open to opinions especially from @isbluis and @mohsenht about where this should be done (UI or pathfinder itself)

[edeutsch]

Does it make sense to limit the number of paths (analyses) on the back end?

or should the back end send them all and the UI should discard more than X?

[mohsenht]

If we want to truncate paths in the backend, I can easily truncate them by sending limit number of paths to the UI.

[dkoslicki]

I had a meeting today with Nishad and the rest of the UI team; they're going to take a look at some of our results to help inform the question of: do we want to limit the number of path, or limit the number of nodes in the knowledge graph. So we should get some guidance/input from them after they've had a chance to look into it a bit more.