ci: revert coverage subprocess patch config

Co-authored-by: Miles Cranmer <miles.cranmer@gmail.com>

Author: MilesCranmerBot

.coveragerc

@@ -1,7 +1,4 @@
 [run]
-# pytest-cov 7 dropped its legacy subprocess coverage mechanism; enable
-# coverage.py's subprocess patch so coverage continues to include subprocesses.
-patch = subprocess
 omit =
     */test/*
 source = pysr