Added ContainerSpawnPoint check for integration test (#25446)

* Added logic for ContainerSpawnPoint checks

* Improved with template function

* fixed nullable

* hehe

* hehe T?

* added type check before cast

* another nullable fix

* and another one

* return to old code (found typo)

* Code cleanup

---------

Co-authored-by: metalgearsloth <comedian_vs_clown@hotmail.com>

Content.Server/Spawners/Components/ISpawnPoint.cs

@@ -0,0 +1,7 @@
+namespace Content.Server.Spawners.Components;
+
+public interface ISpawnPoint
+{
+    SpawnPointType SpawnType { get; set; }
+}
+