Use pragma: no cover to exclude branches from coverage stats

See https://coverage.readthedocs.io/en/7.6.10/excluding.html

dpctl/_init_helper.py

@@ -24,7 +24,7 @@
     and os.path.isfile(os.path.join(sys.exec_prefix, "pyvenv.cfg"))
 )
 
-if is_venv_win32:
+if is_venv_win32:  # pragma: no cover
     # For virtual environments on Windows, add folder
     # with DPC++ libraries to the DLL search path gh-1745
     dll_dir = os.path.join(sys.exec_prefix, "Library", "bin")