6.15.2: pytest is failing in `ipykernel/tests/test_debugger.py::test_stop_on_breakpoint` unit

I'm packaging your module as an rpm package so I'm using the typical PEP517 based build, install and test cycle used on building packages from non-root account.
- `python3 -sBm build -w --no-isolation`
- because I'm calling `build` with `--no-isolation` I'm using during all processes only locally installed modules
- install .whl file in
- run pytest with PYTHONPATH pointing to sitearch and sitelib inside

Here is pytest output:

```console
+ PYTHONPATH=/home/tkloczko/rpmbuild/BUILDROOT/python-ipykernel-6.15.2-2.fc35.x86_64/usr/lib64/python3.8/site-packages:/home/tkloczko/rpmbuild/BUILDROOT/python-ipykernel-6.15.2-2.fc35.x86_64/usr/lib/python3.8/site-packages
+ /usr/bin/pytest -ra
=========================================================================== test session starts ============================================================================
platform linux -- Python 3.8.13, pytest-7.1.2, pluggy-1.0.0
rootdir: /home/tkloczko/rpmbuild/BUILD/ipykernel-6.15.2, configfile: pyproject.toml, testpaths: ipykernel/tests, ipykernel/inprocess/tests
plugins: timeout-2.1.0, flaky-3.7.0
timeout: 300.0s
timeout method: signal
timeout func_only: False
collected 116 items

ipykernel/tests/test_async.py ..ss [ 3%]
ipykernel/tests/test_connect.py ..... [ 7%]
ipykernel/tests/test_debugger.py ...F.... [ 14%]
ipykernel/tests/test_embed_kernel.py ... [ 17%]
ipykernel/tests/test_eventloop.py . [ 18%]
ipykernel/tests/test_heartbeat.py .... [ 21%]
ipykernel/tests/test_io.py .. [ 23%]
ipykernel/tests/test_jsonutil.py sssss [ 27%]
ipykernel/tests/test_kernel.py .ss..........s..s...... [ 47%]
ipykernel/tests/test_kernelspec.py ............. [ 58%]
ipykernel/tests/test_message_spec.py ....................... [ 78%]
ipykernel/tests/test_pickleutil.py ..... [ 82%]
ipykernel/tests/test_start_kernel.py .. [ 84%]
ipykernel/tests/test_zmq_shell.py ...... [ 89%]
ipykernel/inprocess/tests/test_kernel.py s...... [ 95%]
ipykernel/inprocess/tests/test_kernelmanager.py ..... [100%]

================================================================================= FAILURES =================================================================================
_________________________________________________________________________ test_stop_on_breakpoint __________________________________________________________________________

kernel_with_debug =

def test_stop_on_breakpoint(kernel_with_debug):
code = """def f(a, b):
c = a + b
return c

f(2, 3)"""

r = wait_for_debug_request(kernel_with_debug, "dumpCell", {"code": code})
> source = r["body"]["sourcePath"]
E KeyError: 'body'

ipykernel/tests/test_debugger.py:138: KeyError
===Flaky Test Report===

test_embed_kernel_basic passed 1 out of the required 1 times. Success!
test_embed_kernel_namespace passed 1 out of the required 1 times. Success!
test_embed_kernel_reentrant passed 1 out of the required 1 times. Success!
test_subprocess_print passed 1 out of the required 1 times. Success!
test_subprocess_noprint passed 1 out of the required 1 times. Success!
test_subprocess_error passed 1 out of the required 1 times. Success!
test_ipython_start_kernel_userns passed 1 out of the required 1 times. Success!
test_ipython_start_kernel_no_userns passed 1 out of the required 1 times. Success!

===End Flaky Test Report===
=========================================================================== slowest 10 durations ===========================================================================
31.37s call ipykernel/tests/test_kernel.py::test_shutdown_subprocesses
6.32s call ipykernel/tests/test_async.py::test_async_interrupt[asyncio]
3.09s call ipykernel/tests/test_kernel.py::test_control_thread_priority
2.96s call ipykernel/tests/test_kernel.py::test_interrupt_during_input
2.82s call ipykernel/tests/test_kernel.py::test_subprocess_print
2.81s call ipykernel/tests/test_kernel.py::test_interrupt_with_message
2.53s call ipykernel/tests/test_message_spec.py::test_execute_stop_on_error
2.29s call ipykernel/tests/test_embed_kernel.py::test_embed_kernel_reentrant
2.03s call ipykernel/tests/test_kernel.py::test_interrupt_during_pdb_set_trace
1.78s setup ipykernel/tests/test_debugger.py::test_stop_on_breakpoint
========================================================================= short test summary info ==========================================================================
SKIPPED [1] ipykernel/tests/test_async.py:34: Requires trio
SKIPPED [1] ipykernel/tests/test_async.py:34: Requires curio
SKIPPED [1] ipykernel/tests/test_jsonutil.py:36: json_clean is a no-op
SKIPPED [1] ipykernel/tests/test_jsonutil.py:71: json_clean is a no-op
SKIPPED [1] ipykernel/tests/test_jsonutil.py:98: json_clean is a no-op
SKIPPED [1] ipykernel/tests/test_jsonutil.py:104: json_clean is a no-op
SKIPPED [1] ipykernel/tests/test_jsonutil.py:115: json_clean is a no-op
SKIPPED [1] ipykernel/tests/test_kernel.py:61: Currently don't capture during test as pytest does its own capturing
SKIPPED [1] ipykernel/tests/test_kernel.py:73: Currently don't capture during test as pytest does its own capturing
SKIPPED [1] ipykernel/tests/test_kernel.py:290: only run on Windows
SKIPPED [1] ipykernel/tests/test_kernel.py:349: test only on windows
SKIPPED [1] ipykernel/inprocess/tests/test_kernel.py:129: Currently don't capture during test as pytest does its own capturing
FAILED ipykernel/tests/test_debugger.py::test_stop_on_breakpoint - KeyError: 'body'
========================================================== 1 failed, 103 passed, 12 skipped in 103.54s (0:01:43) ===========================================================
```

Here is list of installed modules in build env

```console
Package Version
----------------------------- -----------------
alabaster 0.7.12
asttokens 2.0.5
attrs 22.1.0
Babel 2.10.2
backcall 0.2.0
Brlapi 0.8.3
build 0.8.0
charset-normalizer 2.1.0
codespell 2.1.0
cycler 0.11.0
debugpy 1.6.3
decorator 5.1.1
distro 1.7.0
docutils 0.18.1
editables 0.3
entrypoints 0.4
executing 0.8.3
extras 1.0.0
fixtures 4.0.0
flaky 3.7.0
fonttools 4.37.1
gpg 1.17.1-unknown
hatchling 1.8.1
idna 3.3
imagesize 1.4.1
importlib-metadata 4.12.0
iniconfig 1.1.1
ipykernel 6.15.1
ipyparallel 8.4.1
ipython 8.4.0
jedi 0.18.1
Jinja2 3.1.1
jupyter_client 7.3.5
jupyter_core 4.11.1
kiwisolver 1.4.4
libcomps 0.1.18
louis 3.22.0
markdown-it-py 2.1.0
MarkupSafe 2.1.1
matplotlib 3.5.3
matplotlib-inline 0.1.5
mdit-py-plugins 0.3.0
mdurl 0.1.1
myst-parser 0.18.0
nest-asyncio 1.5.5
numpy 1.23.1
olefile 0.46
packaging 21.3
parso 0.8.3
pathspec 0.9.0
pbr 5.9.0
pep517 0.12.0
pexpect 4.8.0
pickleshare 0.7.5
Pillow 9.2.0
pip 22.2.1
pluggy 1.0.0
prompt-toolkit 3.0.29
psutil 5.9.0
ptyprocess 0.7.0
pure-eval 0.2.2
py 1.11.0
Pygments 2.13.0
PyGObject 3.42.2
pyparsing 3.0.9
pytest 7.1.2
pytest-timeout 2.1.0
python-dateutil 2.8.2
pytz 2022.1
PyYAML 6.0
pyzmq 23.2.0
requests 2.28.1
rpm 4.17.0
setuptools 65.3.0
six 1.16.0
snowballstemmer 2.2.0
Sphinx 5.1.1
sphinxcontrib-applehelp 1.0.2.dev20220730
sphinxcontrib-devhelp 1.0.2.dev20220730
sphinxcontrib_github_alt 1.2
sphinxcontrib-htmlhelp 2.0.0
sphinxcontrib-jsmath 1.0.1.dev20220730
sphinxcontrib-qthelp 1.0.3.dev20220730
sphinxcontrib-serializinghtml 1.1.5
stack-data 0.5.0
testtools 2.5.0
tomli 2.0.1
tornado 6.2
tqdm 4.64.0
traitlets 5.3.0
typing_extensions 4.2.0
urllib3 1.26.12
wcwidth 0.2.5
wheel 0.37.1
zipp 3.8.1
```