Fix deepcopy/pickle of CRS subclasses created from WKT

[DavidVadnais]

Rationale

Fixes: #2571

The code to exercise:

import copy
import cartopy.crs as ccrs
from pyproj import CRS

copy.deepcopy(ccrs.Projection(CRS.from_epsg(4326)))

Before fix

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
Cell In[1], line 5
      2 import cartopy.crs as ccrs
      3 from pyproj import CRS
----> 5 copy.deepcopy(ccrs.Projection(CRS.from_epsg(4326)))

File ~/micromamba/envs/pycodas/lib/python3.11/copy.py:172, in deepcopy(x, memo, _nil)
    170                 y = x
    171             else:
--> 172                 y = _reconstruct(x, memo, *rv)
    174 # If is its own copy, don't memoize.
    175 if y is not x:

File ~/micromamba/envs/pycodas/lib/python3.11/copy.py:265, in _reconstruct(x, memo, func, args, state, listiter, dictiter, deepcopy)
    263 if deep and args:
    264     args = (deepcopy(arg, memo) for arg in args)
--> 265 y = func(*args)
    266 if deep:
    267     memo[id(x)] = y

File ~/project/cartopy/lib/cartopy/crs.py:670, in Projection.__init__(self, *args, **kwargs)
    669 def __init__(self, *args, **kwargs):
--> 670     super().__init__(*args, **kwargs)
    671     self.bounds = None
    672     if self.area_of_use:
    673         # Convert lat/lon bounds to projected bounds.
    674         # Geographic area of the entire dataset referenced to WGS 84
    675         # NB. We can't use a polygon transform at this stage because
    676         # that relies on the existence of the map boundary... the very
    677         # thing we're trying to work out! ;-)

TypeError: CRS.__init__() missing 1 required positional argument: 'proj4_params'

After Fix

Out[1]:
<Geographic 2D CRS: EPSG:4326>
Name: WGS 84
Axis Info [ellipsoidal]:
- Lat[north]: Geodetic latitude (degree)
- Lon[east]: Geodetic longitude (degree)
Area of Use:
- name: World.
- bounds: (-180.0, -90.0, 180.0, 90.0)
Datum: World Geodetic System 1984 ensemble
- Ellipsoid: WGS 84
- Prime Meridian: Greenwich

Implications

__new__ skips __init__, so any __init__ side effects run only from __setstate__ (which calls CRS.__init__).

[DavidVadnais]

I think rerunning the job should fix this but I'm not certain.

[greglucas]

Thanks @DavidVadnais!