`httpx==1.0.dev1` makes the "Test Prereleases" CI check fail

[jtpio]

As noticed in #7689 and other recent PRs:

https://github.com/jupyter/notebook/actions/runs/16725211938/job/47338909982?pr=7689

For reference:

• Pin to httpx<1 jupyterlab/jupyterlab#17746
• [1.0.dev1] Reinstate `httpx.__version__`? encode/httpx#3619
• #jupyterlab > Release coordination @ 💬

[jtpio]

httpx.__version__ seems to be back 1.0.dev2: encode/httpx#3619 (comment)

But now getting:

Traceback (most recent call last):
        File "/tmp/pip-build-env-fcrtbo48/overlay/bin/jupyter-labextension", line 5, in <module>
          from jupyterlab.labextensions import main
        File "/tmp/pip-build-env-fcrtbo48/overlay/lib/python3.13/site-packages/jupyterlab/labextensions.py", line 34, in <module>
          from .labapp import LabApp
        File "/tmp/pip-build-env-fcrtbo48/overlay/lib/python3.13/site-packages/jupyterlab/labapp.py", line 46, in <module>
          from .extensions import MANAGERS as EXT_MANAGERS
        File "/tmp/pip-build-env-fcrtbo48/overlay/lib/python3.13/site-packages/jupyterlab/extensions/__init__.py", line 12, in <module>
          from .pypi import PyPIExtensionManager
        File "/tmp/pip-build-env-fcrtbo48/overlay/lib/python3.13/site-packages/jupyterlab/extensions/pypi.py", line 91, in <module>
          client: httpx.AsyncClient,
                  ^^^^^^^^^^^^^^^^^
      AttributeError: module 'httpx' has no attribute 'AsyncClient'