gh-35627: Remove jupyter-packaging for conda
    
<!-- Please provide a concise, informative and self-explanatory title.
-->
<!-- Don't put issue numbers in the title. Put it in the Description
below. -->
<!-- For example, instead of "Fixes #12345", use "Add a new method to
multiply two integers" -->

### 📚 Description
We don't need jupyter-packaging (explicitly, maybe only some
dependencies need it, depending on versions) so conda is able to build
the dependency tree. Part of
#34626. Moreover, its not working
with the conda 3.11 test:
https://github.com/sagemath/sage/actions/runs/4906896658/jobs/8761652608

<!-- Describe your changes here in detail. -->
<!-- Why is this change required? What problem does it solve? -->
<!-- If this PR resolves an open issue, please link to it here. For
example "Fixes #12345". -->
<!-- If your change requires a documentation PR, please link it
appropriately. -->

### 📝 Checklist

<!-- Put an `x` in all the boxes that apply. It should be `[x]` not `[x
]`. -->

- [x] The title is concise, informative, and self-explanatory.
- [x] The description explains in detail what this PR is about.
- [x] I have linked a relevant issue or discussion.
- [ ] I have created tests covering the changes.
- [ ] I have updated the documentation accordingly.

### ⌛ Dependencies

<!-- List all open PRs that this PR logically depends on
- #12345: short description why this is a dependency
- #34567: ...
-->

<!-- If you're unsure about any of these, don't hesitate to ask. We're
here to help! -->
    
URL: #35627
Reported by: Tobias Diez
Reviewer(s): Matthias Köppe

Author: Release Manager

build/pkgs/jupyter_packaging/distros/conda.txt

@@ -1 +1 @@
-jupyter-packaging
+# jupyter-packaging  # only a build dependency, not needed at runtime; conda package does not support Python 3.11 as of 2023-05