juliacall fails from subprocess if already initialied

**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 https://github.com/JuliaPy/PythonCall.jl/issues/77

Running this
```mp.py
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:

```

**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.

Start by running the multiprocessing reproducer in the issue with Python 3.13, Julia 1.11.5, and the listed JuliaCall/PythonCall versions, including PYTHON_JULIACALL_HANDLE_SIGNALS=yes. Read the related PythonCall.jl issue 77 for context. Done means the subprocess call works, or the package limitation and affected configuration are clearly documented.

Written by the indexing model from the issue text.