Update GeoPandas example for geopandas 1.0+

[mosh3eb]

The example was using the 'world' dataset which was removed in geopandas 1.0. Updated to use the geodatasets package for v1.0+ with a fallback to the old approach for older versions.

This keeps the example working across all geopandas versions.

Fixes #4778

Documentation PR

• I have seen the [doc/README.md](https://github.com/plotly/plotly.py/blob/main/doc/README.md) file.
• This change runs in the current version of Plotly on PyPI and targets the doc-prod branch OR it targets the main branch.
• If this PR modifies the first example in a page or adds a new one, it is a px example if at all possible.
• Every new/modified example has a descriptive title and motivating sentence or paragraph.
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• New/modified remote datasets are loaded from https://plotly.github.io/datasets and added to https://github.com/plotly/datasets.
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• Liberal use is made of fig.add_* and fig.update_* rather than go.Figure(data=..., layout=...).
• Specific adders and updaters like fig.add_shape and fig.update_xaxes are used instead of big fig.update_layout calls.
• fig.show() is at the end of each example.
• plotly.plot() and plotly.iplot() are not used in any example.
• Named colors are used instead of hex codes wherever possible.
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