[Build] Unable to build the ```source distribution```

### Describe the issue

there is no ```source distribution``` in pypi and unable to build the source distribution tried to build using ``` python -m build --sdist```

``` Necessity ``` : Trying to build the emscripten package for onnxruntime to use this onnxruntime inside pyodide environment kindly do the needful

``` To Reproduce ``` : clone the repo and execute the build command

### Urgency

``` URGENT ``` unable to build the emscripten package for the onnxruntime package inside pyodide build.

### Target platform

MAC M1

### Build script

``` python -m build --wheel ```

### Error / output

```
* Creating virtualenv isolated environment...
* Installing packages in isolated environment... (setuptools >= 40.8.0, wheel)
* Getting dependencies for sdist...
Traceback (most recent call last):
File "/Users/kishore-17103/.local/lib/python3.11/site-packages/pep517/in_process/_in_process.py", line 351, in
main()
File "/Users/kishore-17103/.local/lib/python3.11/site-packages/pep517/in_process/_in_process.py", line 333, in main
json_out['return_val'] = hook(**hook_input['kwargs'])
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/Users/kishore-17103/.local/lib/python3.11/site-packages/pep517/in_process/_in_process.py", line 285, in get_requires_for_build_sdist
return hook(config_settings)
^^^^^^^^^^^^^^^^^^^^^
File "/private/var/folders/q9/ms4_8l4970q525dlsjp_b9n0x6l4j9/T/build-env-gfmk7js3/lib/python3.11/site-packages/setuptools/build_meta.py", line 358, in get_requires_for_build_sdist
return self._get_build_requires(config_settings, requirements=[])
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/private/var/folders/q9/ms4_8l4970q525dlsjp_b9n0x6l4j9/T/build-env-gfmk7js3/lib/python3.11/site-packages/setuptools/build_meta.py", line 325, in _get_build_requires
self.run_setup()
File "/private/var/folders/q9/ms4_8l4970q525dlsjp_b9n0x6l4j9/T/build-env-gfmk7js3/lib/python3.11/site-packages/setuptools/build_meta.py", line 507, in run_setup
super(_BuildMetaLegacyBackend, self).run_setup(setup_script=setup_script)
File "/private/var/folders/q9/ms4_8l4970q525dlsjp_b9n0x6l4j9/T/build-env-gfmk7js3/lib/python3.11/site-packages/setuptools/build_meta.py", line 341, in run_setup
exec(code, locals())
File "", line 18, in
ModuleNotFoundError: No module named 'packaging'

ERROR Backend subproccess exited when trying to invoke get_requires_for_build_sdist
```

### Visual Studio Version

_No response_

### GCC / Compiler Version

_No response_

Start by reproducing `python -m build --sdist` from a clean checkout and inspect the repository's Python packaging and build configuration; no specific files or tests are named in the issue. Done means the source distribution builds without the reported `packaging` import failure, with the relevant emscripten or Pyodide workflow still usable.

Written by the indexing model from the issue text.