Avoid creating files in current directory during tests

[stefan6419846]

Running the tests will currently generate (and delete) temporary files inside the current working directory. This does not look right and should probably be replaced by appropriate temporary directories/files instead. Example test:

pypdf/tests/test_reader.py

Line 221 in 7579329

def test_get_images(src, expected_images):

Environment

Which environment were you using when you encountered the problem?

$ python -m platform
Linux-5.14.21-150400.24.100-default-x86_64-with-glibc2.31

$ python -c "import pypdf;print(pypdf._debug_versions)"
pypdf==4.0.1, crypt_provider=('local_crypt_fallback', '0.0.0'), PIL=10.1.0