Merge PR #23978 into master

* refs/pull/23978/head:
	mgr: add get_latest_counter() to C++ -> Python interface.
	mgr: remove PerfCounterInstance::get_current()
	mgr: remove PyFormatter copy constructor; shouldn't be called

Reviewed-by: John Spray <john.spray@redhat.com>

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

diff --cc src/pybind/mgr/mgr_module.py
Simple merge