BUG: Gracefully handle calling orient() on empty polygon

[sea-bass]

I recently had a user run into an error they couldn't figure out. Upon analyzing the issue, I pinpointed it to a very simple use case of trying to call shapely.geometry.polygon.orient() on an empty Polygon as follows:

from shapely.geometry import Polygon
from shapely.geometry.polygon import orient
orient(Polygon())

This yields the following error:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/sebastian/python-virtualenvs/pyrobosim/lib/python3.12/site-packages/shapely/geometry/polygon.py", line 346, in orient
    if signed_area(ring) / s >= 0.0:
       ^^^^^^^^^^^^^^^^^
  File "/home/sebastian/python-virtualenvs/pyrobosim/lib/python3.12/site-packages/shapely/algorithms/cga.py", line 11, in signed_area
    xs, ys = np.vstack([coords, coords[1]]).T
                                ~~~~~~^^^
IndexError: index 1 is out of bounds for axis 0 with size 0

Here is a simple check on polygon emptiness to prevent this in the future!

[coveralls]

Pull Request Test Coverage Report for Build 13128809702

Details

• 2 of 2 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.3%) to 87.675%

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Totals
Change from base Build 13060116458:	0.3%
Covered Lines:	2568
Relevant Lines:	2929

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💛 - Coveralls

[sgillies]

Thanks @sea-bass !