Add static "IsPowered" method (#8434)

* Add static "IsPowered" method

* Use IsPowered in more places

Co-authored-by: wrexbe <wrexbe@protonmail.com>

Content.Server/Power/EntitySystems/StaticPowerSystem.cs

@@ -0,0 +1,13 @@
+using Content.Server.Power.Components;
+
+namespace Content.Server.Power.EntitySystems;
+
+public static class StaticPowerSystem
+{
+    // Using this makes the call shorter.
+    // ReSharper disable once UnusedParameter.Global
+    public static bool IsPowered(this EntitySystem system, EntityUid uid, IEntityManager entManager, ApcPowerReceiverComponent? receiver = null)
+    {
+        return entManager.TryGetComponent<ApcPowerReceiverComponent>(uid, out receiver) && receiver.Powered;
+    }
+}