Fix test_initial_state() test failure on apple silicon.

[jcheek]

Fix test failure on Apple Silicon.

(Kokoro-FastAPI) Macximum (upstream-master %=):~/scm/Kokoro-FastAPI$ uv run pytest
FAILED api/tests/test_kokoro_v1.py::test_initial_state - AssertionError: assert 'mps' in ['cuda', 'cpu']
======================================= 1 failed, 81 passed, 9 warnings in 1.56s =======================================

[jcheek]

ty @faltiska , hoping this will be merged @remsky 8-)