[TF2] Enable War Paint compatibility on the Ambassador

[ShadowMan44]

The Ambassador was set up to be compatible with War Paints, shown in the game files it has all the different texture files meant for weapons with WP's, but Valve just never enabled them. This might have been due to the fact that the engravings are still visible when you have skins on them, and some people may not like it. But there's a simple fix you could do by simply removing the engravings on the WP base textures. It's a small price to pay for being able to have a new weapon usable with War Paints, and boy I'm sure there's people out there who'd be pleased.