Remove PoolSettings.ExtraPrototypes option (#18678)

Content.IntegrationTests/PoolManager.Prototypes.cs

@@ -0,0 +1,38 @@
+#nullable enable
+using System.Collections.Generic;
+using System.Reflection;
+using Robust.Shared.Utility;
+
+namespace Content.IntegrationTests;
+
+// Partial class for handling the discovering and storing test prototypes.
+public static partial class PoolManager
+{
+    private static List<string> _testPrototypes = new();
+
+    private const BindingFlags Flags = BindingFlags.Static
+                                       | BindingFlags.NonPublic
+                                       | BindingFlags.Public
+                                       | BindingFlags.DeclaredOnly;
+
+    private static void DiscoverTestPrototypes(Assembly? assembly = null)
+    {
+        assembly ??= typeof(PoolManager).Assembly;
+        _testPrototypes.Clear();
+
+        foreach (var type in assembly.GetTypes())
+        {
+            foreach (var field in type.GetFields(Flags))
+            {
+                if (!field.HasCustomAttribute<TestPrototypesAttribute>())
+                    continue;
+
+                var val = field.GetValue(null);
+                if (val is not string str)
+                    throw new Exception($"TestPrototypeAttribute is only valid on non-null string fields");
+
+                _testPrototypes.Add(str);
+            }
+        }
+    }
+}