The nearest api is wrong on zoom level 15

For this request: https://prod-k8s.treetracker.org/query/gis/location/nearest?zoom_level=15&lat=-15.753204919146587&lng=46.369900703430176&planter_id=7703 the return is a location of tree, this is wrong, because on the web map, the zoom level is for `cluster` than `tree`, so we need to return the nearest `cluster`.

---

Some hints:

- Please read our readme for more information/guide/tutorial.
- Here is [an engineering book](https://greenstand.gitbook.io/engineering/) in Greenstand.
- To know more about our organization, visit our [website](https://greenstand.org).
- If you want to join the slack community (some resources need the community member's permission), please leave your email address.