setup_orekit_data() fails when orekitdata library not available

To reproduce:

• Install orekit_jpype + matplotlib + ipykernel in a clean venv
• Do not install the orekitdata library
• run examples/Example_EarthObservation_-_Attitude_Sequence-jpype.ipynb
• setup_orekit_data() returns the following error:

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
Cell In[4], line 1
----> 1 setup_orekit_data()

File /media/ssd/git/orekit_jpype/orekit_jpype/pyhelpers.py:162, in setup_orekit_data(filenames, from_pip_library)
    151 def setup_orekit_data(filenames: Union[str, List[str], None] = None, from_pip_library: bool = True) -> None:
    152     """
    153     Sets up the orekit data from a file, folder or list of files/folders.
    154     Can also load the data from the `orekitdata` python library. (default)
   (...)
    159     
    160     """
--> 162     setup_orekit_curdir(filename=filenames, from_pip_library=from_pip_library)

File /media/ssd/git/orekit_jpype/orekit_jpype/pyhelpers.py:119, in setup_orekit_curdir(filename, from_pip_library)
    114         print(f"""Failed to load orekitdata library.
    115               Install with `pip install git+https://gitlab.orekit.org/orekit/orekit-data.git`
    116               Will try to load Orekit data using the folder or filename {filename}""")
    118 if not data_load_from_library_sucessful:
--> 119     datafile = File(filename)
    120     if not datafile.exists():
    121         print('File or folder:', datafile.getAbsolutePath(), ' not found')

TypeError: Ambiguous overloads found for constructor java.io.File(NoneType) between:
	public java.io.File(java.lang.String)
	public java.io.File(java.net.URI)

Whereas I tested the same thing with the Orekit JCC wrapper, it does not have this error.

When installing the orekitdata library, the error vanished as expected.