Fix callbacks for pre-1.02x SDKs

[NicknineTheEagle]

SDK version 1.02x added an overload for CCallbackBase::Run. Because of how MSVC handles virtual function overloads, this changed the order of functions in vtable from 1.02, which breaks old games. This PR adds a workaround for this issue that uses a wrapper for the old CCallbackBase variant.

Note that this only affects steam_api.dll replacement, loader + steamclient.dll setup already works fine as is.

More about this problem with vtables and overloads:
https://stackoverflow.com/questions/61542063/inversion-of-generated-vtable-functions-order-for-functions-with-the-same-name
https://stackoverflow.com/questions/22059092/visual-c-methods-in-vfptr-in-reverse-order

[Detanup01]

Lmao, ms..

[camerasfirmwares]

Don't do that, instead rename the functions in the way they are in memory layout. So you don't have an overload or wrapper.

[NicknineTheEagle]

Tell that to Valve, not us. :P We're stuck with their mess.

[camerasfirmwares]

There was a reason why I said it here and not to Valve but, ok, then just ignore my comment.

[Detanup01]

Propose the change then I dont know much C++ to do anything either so

[NicknineTheEagle]

The issue isn't that our vtable order doesn't match Valve's, the issue is that Valve's own vtable order is inconsistent between old and new SDKs on Windows because they added an overload. Renaming the overload on our end wouldn't solve anything. Like I said, this is Valve's mess that we're stuck with.