TST: fix point creation in clip test suite

[martinfleis]

This should fix the failures on CI in an env with shapely 2.0b2. shapely/shapely#1590 uncovered that we were passing a list of tuples to a Point constructor. While old shapely uses only the first tuple and ignores the rest, shapely 2.0b2 correctly raises an error.

[m-richards]

Looks fine to me. Docstrings on these fixtures are a bit misleading but that doesn't need to be fixed here.

[m-richards]

(From Martin's comment in the linked shapely issue)

GeoPandas CI fails on this
Point([(2, 3), (11, 4), (7, 2), (8, 9), (1, 13)])
Which I'd say is a correct behaviour. I don't really understand what is the intention of this line.

Just doing some archeology on this,
seems to have been introduced here:
lwasser@67c58c0#diff-999030931f6802617e56e4c04679840188538ca61816e9ee97d9fac0763563dc
and then copied through into the analogous test for geometrycollections. Seems fairly likely that the intent was to actually add a point.