[TF2] Don't discard ammo on the Force-a-Nature if the clip is full

[num-get]

Basically https://github.com/ValveSoftware/source-sdk-2013/pull/1398 but for Scout's Force-a-Nature.

Before:

https://github.com/user-attachments/assets/0f22b0ac-3f92-4e48-a4e0-516da1a83b42

After:

https://github.com/user-attachments/assets/ef83ba6f-72d7-4c9c-871f-e3da3c89ade3

[Flpstrike]

I'm only going to like this idea if Valve adds a 1-shell only reload animation