Remove upper limit on version of SciPy and fix resulting test failures

[namurphy]

In #2472, updating to scipy == 1.12.0 led to four new errors in test_grids.py. I'm not sure what the cause is, but it'd be worth reading through the release notes for SciPy 1.12.0. It'd be really helpful to get this fixed before releasing 2024.1.0 next week.

The errors are:

__________________________________ test_nonuniform_cartesian_NN_interp[pos0-quantities0-expected0] __________________________________
tests/test_grids.py:710: in test_nonuniform_cartesian_NN_interp
pout = nonuniform_cartesian_grid.nearest_neighbor_interpolator(pos, *quantities)
../utils/decorators/helpers.py:58: in wrapper
return f(*bound_args.args, **bound_args.kwargs)
grids.py:1423: in nearest_neighbor_interpolator
vals = self._interp_quantities[i, :]
E   IndexError: arrays used as indices must be of integer (or boolean) type
__________________________________ test_nonuniform_cartesian_NN_interp[pos1-quantities1-expected1] __________________________________
tests/test_grids.py:710: in test_nonuniform_cartesian_NN_interp
pout = nonuniform_cartesian_grid.nearest_neighbor_interpolator(pos, *quantities)
../utils/decorators/helpers.py:58: in wrapper
return f(*bound_args.args, **bound_args.kwargs)
grids.py:1423: in nearest_neighbor_interpolator
vals = self._interp_quantities[i, :]
E   IndexError: arrays used as indices must be of integer (or boolean) type
__________________________________ test_nonuniform_cartesian_NN_interp[pos2-quantities2-expected2] __________________________________
tests/test_grids.py:710: in test_nonuniform_cartesian_NN_interp
pout = nonuniform_cartesian_grid.nearest_neighbor_interpolator(pos, *quantities)
../utils/decorators/helpers.py:58: in wrapper
return f(*bound_args.args, **bound_args.kwargs)
grids.py:1423: in nearest_neighbor_interpolator
vals = self._interp_quantities[i, :]
E   IndexError: arrays used as indices must be of integer (or boolean) type
______________________________________ test_nonuniform_cartesian_nearest_neighbor_interpolator ______________________________________
tests/test_grids.py:736: in test_nonuniform_cartesian_nearest_neighbor_interpolator
pout = grid.nearest_neighbor_interpolator(pos, "x", persistent=True)
../utils/decorators/helpers.py:58: in wrapper
return f(*bound_args.args, **bound_args.kwargs)
grids.py:1423: in nearest_neighbor_interpolator
vals = self._interp_quantities[i, :]
E   IndexError: arrays used as indices must be of integer (or boolean) type