test: apply copilot suggestions for crypto_utils

Signed-off-by: adityashirsatrao007 <adityashirsatrao007@gmail.com>

Author: adityashirsatrao007

tests/unit/crypto_utils_test.py

@@ -1,5 +1,6 @@
 """Unit tests for crypto_utils module."""
 from cryptography.hazmat.primitives.asymmetric import ec
+import pytest
 
 from hiero_sdk_python.utils.crypto_utils import (
     compress_point_unchecked,
@@ -8,6 +9,8 @@
     keccak256,
 )
 
+pytestmark = pytest.mark.unit
+
 
 def test_keccak256():
     """Test keccak256 hashing."""