juliacall fails from subprocess if already initialied

[dpinol]

Affects: JuliaCall

Describe the bug
If juliacall is imported, and then a python subprocess uses juliacall, it fails at least when executed with PYTHON_JULIACALL_HANDLE_SIGNALS=yes .
If it's a package limitation, I guess it should be clearly documented. Related to #77

Running this

import os
from multiprocessing import Process
import juliacall

def use_juliacall() -> None:
    # import juliacall

    print(os.getpid())
    juliacall.Base.println("hola")


p = Process(target=use_juliacall)
p.start()
p.join()

I get

Process Process-1:
Traceback (most recent call last):
  File "/home/dani/.pyenv/versions/3.13.4/lib/python3.13/multiprocessing/process.py", line 313, in _bootstrap
    self.run()
    ~~~~~~~~^^
  File "/home/dani/.pyenv/versions/3.13.4/lib/python3.13/multiprocessing/process.py", line 108, in run
    self._target(*self._args, **self._kwargs)
    ~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/dani/source/repos/sc-tools/scpytools/mp.py", line 9, in use_juliacall
    juliacall.Base.println("hola")
    ^^^^^^^^^^^^^^^^^^^^^^
  File "/home/dani/.julia/packages/PythonCall/L4cjh/src/JlWrap/any.jl", line 249, in __getattr__
    return self._jl_callmethod($(pyjl_methodnum(pyjlany_getattr)), k)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^
juliacall.JuliaError: <exception str() failed>

Your system
Please provide detailed information about your system:

• Ubuntu 25.04
• python 3.13.4
• julia 1.11.5
• PythonCall, JuliaCall: 0.9.25

Package   Version
--------- -------
filelock  3.18.0
juliacall 0.9.25
juliapkg  0.1.17
pip       25.1.1
semver    3.0.4

>>> juliapkg.status()
JuliaPkg Status
/home/dani/.virtualenvs/deleteme/julia_env/pyjuliapkg/juliapkg.json (empty project)
Julia 1.11.5 @ /home/dani/.julia/juliaup/julia-1.11.5+0.x64.linux.gnu/bin/julia

Additional context
Add any other context about the problem here.