test: Update video generation tests to use Veo 3.1 Lite

PiperOrigin-RevId: 952485190

Author: speedstorm1

google/genai/tests/shared/models/test_generate_videos.py

@@ -18,8 +18,8 @@
 from .... import types
 from ... import pytest_helper
 
-VEO_MODEL_LATEST_VERTEX = "veo-2.0-generate-001"
-VEO_MODEL_LATEST_GEMINI = "veo-3.1-generate-preview"
+VEO_MODEL_LATEST_VERTEX = "veo-3.1-lite-generate-001"
+VEO_MODEL_LATEST_GEMINI = "veo-3.1-lite-generate-preview"
 
 
 test_table: list[pytest_helper.TestTableItem] = [
@@ -30,7 +30,7 @@
             prompt="Man with a dog",
         ),
         exception_if_mldev=(
-            "models/veo-2.0-generate-001 is not found for API version v1beta"
+            "models/veo-3.1-lite-generate-001 is not found for API version v1beta"
         ),
     ),
     pytest_helper.TestTableItem(