cuda.core: fix test_utils parametrize collection error on pytest 8.4+

`@pytest.mark.parametrize("in_arr,", _cpu_array_samples())` has a stray trailing
comma in the names string. Older pytest tolerated it, but pytest 8.4+ (used in
CI) treats `"in_arr,"` as a request to unpack each argvalue across multiple
names — so a 3-element sample array becomes "3 values for 1 name" and the whole
test session aborts at collection ("1 error during collection"), failing every
GPU test job. Drop the trailing comma so each array sample is one parameter.

Pre-existing (introduced in #1894, also on main); fixing here to unblock CI.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: rparolin

cuda_core/tests/test_utils.py

@@ -148,7 +148,7 @@ def _cpu_array_samples():
     return samples
 
 
-@pytest.mark.parametrize("in_arr,", _cpu_array_samples())
+@pytest.mark.parametrize("in_arr", _cpu_array_samples())
 class TestViewCPU:
     def test_args_viewable_as_strided_memory_cpu(self, in_arr):
         @args_viewable_as_strided_memory((0,))