Rework metadata struct loading to use new struct versioning

Il2CppInspector.Common/Next/BinaryMetadata/Il2CppTokenIndexMethodTuple.cs

@@ -3,13 +3,12 @@
 namespace Il2CppInspector.Next.BinaryMetadata;
 
 [VersionedStruct]
-public partial struct Il2CppTokenIndexMethodTuple
+public partial record struct Il2CppTokenIndexMethodTuple
 {
     public uint Token;
     public int Index;
 
-    [CustomSerialization("reader.ReadNUInt();", "is32Bit ? 4 : 8")]
-    public ulong Method; // void**
+    public PrimitivePointer<Il2CppMethodPointer> Method; // void**
 
     public uint GenericMethodIndex;
 }