Eager load location#suppliers to improve performance (#2402)

- When a supplier_id was not provided, there was no eager loading.

app/services/locations/finder.rb

@@ -58,6 +58,8 @@ def apply_nomis_agency_filters(scope)
     end
 
     def apply_supplier_filters(scope)
+      scope = scope.includes(:suppliers)
+
       return scope unless filter_params.key?(:supplier_id)
 
       scope = scope.includes(:suppliers).where(suppliers: { id: split_params(:supplier_id) })