Merge PR #67515 into wip-pdonnell-testing-20260421.200156

* refs/pull/67515/head:
	mgr/Gil.cc: simplify Gil(), ~Gil()
	mgr/Gil.cc: do not use PyGILState_Check()
	mgr: add mgr_subinterpreter_modules config
	python-common/.../service_spec: implement ServiceSpec.__getnewargs__ to allow unpickle to work correctly
	mgr: serialize python objects sent between subinterpreters via remote

diff --cc src/common/options/mgr.yaml.in
Simple merge

diff --cc src/mgr/ActivePyModules.cc
Simple merge

diff --cc src/mgr/ActivePyModules.h
Simple merge

diff --cc src/mgr/BaseMgrModule.cc
Simple merge