Missing <session>.reg.json for analytics

[mtitov]

Example of the error message (FileNotFoundError: ...<session>.reg.json)

Traceback (most recent call last):
  File "/home/runner/work/radical.pilot/radical.pilot/testenv/bin/rp_inspect/plot_util_2.py", line 280, in <module>
    main()
  File "/home/runner/work/radical.pilot/radical.pilot/testenv/bin/rp_inspect/plot_util_2.py", line 168, in main
    session = ra.Session.create(src=src, stype=stype)
  File "/home/runner/work/radical.pilot/radical.pilot/testenv/lib/python3.8/site-packages/radical/analytics/session.py", line 303, in create
    session = Session(src, stype, sid, _entities, _init)
  File "/home/runner/work/radical.pilot/radical.pilot/testenv/lib/python3.8/site-packages/radical/analytics/session.py", line 115, in __init__
    rpu.get_session_description(sid=sid, src=self._src)
  File "/home/runner/work/radical.pilot/radical.pilot/testenv/lib/python3.8/site-packages/radical/pilot/utils/prof_utils.py", line 578, in get_session_description
    reg = ru.read_json('%s/%s.reg.json' % (src, sid))
  File "/home/runner/work/radical.pilot/radical.pilot/testenv/lib/python3.8/site-packages/radical/utils/json_io.py", line 28, in read_json
    with ru_open(fname) as f:
  File "/home/runner/work/radical.pilot/radical.pilot/testenv/lib/python3.8/site-packages/radical/utils/misc.py", line 829, in ru_open
    return open(*args, **kwargs)
FileNotFoundError: [Errno 2] No such file or directory: 'rp.session.fv-az1501-188.runner.020047.0000/rp.session.fv-az1501-188.runner.020047.0000.reg.json'

Source: https://github.com/radical-cybertools/radical.pilot/actions/runs/11940560880/job/33283479710?pr=3260

I think this PR caused it - radical-cybertools/radical.utils#426