[test]: include ltx2_3_base in expected LTX-2 preset set

hao-ai-lab#1397 added the ltx2_3_base preset but test_ltx2_presets_registered
still asserts only 3 presets, so it fails on current main. Drive-by
fix to unblock CI for this PR. Pre-existing bug, surfaced because
this PR also touches CI-running test files.

Author: Mister-Raggs

fastvideo/tests/api/test_presets.py

@@ -334,7 +334,7 @@ def test_ltx2_presets_registered(self) -> None:
         import fastvideo.registry  # noqa: F401
         presets = get_presets_for_family("ltx2")
         names = {p.name for p in presets}
-        assert names == {"ltx2_base", "ltx2_distilled", "ltx2_two_stage"}
+        assert names == {"ltx2_base", "ltx2_3_base", "ltx2_distilled", "ltx2_two_stage"}
 
     def test_ltx2_base_lookup(self) -> None:
         import fastvideo.registry  # noqa: F401