Fix transparency regression for draw-last DFFs with active alpha test

[compromissado]

Summary

Restores the dual-pass transparency behavior used in release/1.6.0 for blended 3D primitives that write to the depth buffer.

In 1.7, the #5006 change skips the second transparency pass when alpha test is enabled with ALPHAREF > 2. This can cause incorrect transparency and lighting in custom draw_last DFF models that use soft texture alpha.

This removes that alpha-test gate from both primitive draw paths:

• CDirect3DEvents9::OnDrawPrimitive
• CDirect3DEvents9::OnDrawIndexedPrimitive

The existing constraints remain unchanged: the dual pass still only applies to blended, depth-writing, non-PositionT 3D draws. HUD and screen-space rendering remain excluded.

Reproduction

Load a custom DFF with smooth/partial texture alpha and enable its transparency:

engineReplaceModel(dff, modelId, true)

--additional
engineSetModelFlag(modelId, "draw_last", true)
engineSetModelFlag(modelId, "additive", true)

With alpha test active, the #5006 condition prevents the second transparency pass, causing the rendering regression shown below.

Before

After

Testing

Built Release|Win32 successfully.

Tested in-game with a custom model using alpha transparency.

Confirmed that the interior no longer exhibits the transparency/lighting regression.
Restores the same dual-pass decision rule used by the latest release/1.6.0 branch.