Scatter plot bugging out when there's only one professor.

[frankcholula]

Error message here

File "/mount/src/supervised/supervised/main.py", line 265, in <module>
    create_scatter_plot()
File "/mount/src/supervised/supervised/main.py", line 231, in create_scatter_plot
    fig = px.scatter(
          ^^^^^^^^^^^
File "/home/adminuser/venv/lib/python3.12/site-packages/plotly/express/_chart_types.py", line 69, in scatter
    return make_figure(args=locals(), constructor=go.Scatter)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/adminuser/venv/lib/python3.12/site-packages/plotly/express/_core.py", line 2477, in make_figure
    args = build_dataframe(args, constructor)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/adminuser/venv/lib/python3.12/site-packages/plotly/express/_core.py", line 1727, in build_dataframe
    df_output, wide_id_vars = process_args_into_dataframe(
                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/adminuser/venv/lib/python3.12/site-packages/plotly/express/_core.py", line 1438, in process_args_into_dataframe
    df_output = nw.from_dict(df_output)
                ^^^^^^^^^^^^^^^^^^^^^^^
File "/home/adminuser/venv/lib/python3.12/site-packages/narwhals/stable/v1/__init__.py", line 2143, in from_dict
    _from_dict_impl(
File "/home/adminuser/venv/lib/python3.12/site-packages/narwhals/functions.py", line 498, in _from_dict_impl
    aligned_data[key] = broadcast_align_and_extract_native(
                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/adminuser/venv/lib/python3.12/site-packages/narwhals/_pandas_like/utils.py", line 124, in broadcast_align_and_extract_native
    s.__class__(s.iloc[0], index=lhs_index, dtype=s.dtype, name=rhs.name),
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/adminuser/venv/lib/python3.12/site-packages/pandas/core/series.py", line 575, in __init__
    com.require_length_match(data, index)
File "/home/adminuser/venv/lib/python3.12/site-packages/pandas/core/common.py", line 573, in require_length_match
    raise ValueError(

[MarcoGorelli]

hi - this might be a bug in narwhals? if you make a runnable example i can take a look