Remove reference to mac part of tests in linux test yml

Author: samanklesaria

.github/workflows/unittest-linux-cpu.yml

@@ -74,5 +74,5 @@ jobs:
                 export TORCHAUDIO_TEST_ALLOW_SKIP_IF_NO_SOX_DECODER=true
                 export TORCHAUDIO_TEST_ALLOW_SKIP_IF_NO_SOX_ENCODER=true
                 export TORCHAUDIO_TEST_ALLOW_SKIP_IF_NO_FFMPEG=true
-                pytest torchaudio_unittest -k "not torchscript and not fairseq and not demucs ${PYTEST_K_EXTRA}"
+                pytest torchaudio_unittest -k "not torchscript and not fairseq and not demucs"
                 echo "::endgroup::"