Fix compiler warnings in equipment monitor

- Prefix unused alert variables with underscore
- Remove unused test_env?/0 function

All warnings resolved, compilation clean with --warnings-as-errors

lib/towerops/monitoring/equipment_monitor.ex

@@ -144,7 +144,7 @@ defmodule Towerops.Monitoring.EquipmentMonitor do
               "Equipment is not responding to ping"
             end
 
-          {:ok, alert} =
+          {:ok, _alert} =
             Alerts.create_alert(%{
               equipment_id: equipment.id,
               alert_type: :equipment_down,
@@ -178,7 +178,7 @@ defmodule Towerops.Monitoring.EquipmentMonitor do
             "Equipment is now responding to ping"
           end
 
-        {:ok, alert} =
+        {:ok, _alert} =
           Alerts.create_alert(%{
             equipment_id: equipment.id,
             alert_type: :equipment_up,
@@ -221,9 +221,4 @@ defmodule Towerops.Monitoring.EquipmentMonitor do
   defp via_tuple(equipment_id) do
     {:via, Registry, {Towerops.Monitoring.Registry, equipment_id}}
   end
-
-  defp test_env? do
-    config = Application.get_env(:towerops, Towerops.Repo, [])
-    Keyword.get(config, :pool) == Ecto.Adapters.SQL.Sandbox
-  end
 end