Angle wrapping fails for PiecewiseNormSpatialModel

[StFroese]

I came across this problem in #5082

Example

Create PiecewiseNormSpatialModel

from gammapy.maps import WcsGeom, MapCoord
import astropy.units as u

geom = WcsGeom.create(skydir=(0, 0), npix=(2, 2), binsz=0.3, frame="galactic")
coords = MapCoord.create(geom.footprint)
coords["lon"] *= u.deg
coords["lat"] *= u.deg

model = PiecewiseNormSpatialModel(coords, frame="galactic")
model.to_dict()

Out[104]: 
{'spatial': {'type': 'PiecewiseNormSpatialModel',
  'frame': 'galactic',
  'parameters': [{'name': 'norm_0', 'value': 1.0},
   {'name': 'norm_1', 'value': 1.0},
   {'name': 'norm_2', 'value': 1.0},
   {'name': 'norm_3', 'value': 1.0}],
  'lon': {'data': [0.15, 0.15, -0.14999999999997726, -0.14999999999997726],
   'unit': 'deg'},
  'lat': {'data': [-0.15, 0.15, 0.15, -0.15], 'unit': 'deg'}}}

Creating a new instance from the dict changes the lon values:

PiecewiseNormSpatialModel.from_dict(model.to_dict()).to_dict()

{'spatial': {'type': 'PiecewiseNormSpatialModel',
  'frame': 'galactic',
  'parameters': [{'name': 'norm_0', 'value': 1.0},
   {'name': 'norm_1', 'value': 1.0},
   {'name': 'norm_2', 'value': 1.0},
   {'name': 'norm_3', 'value': 1.0}],
  'lon': {'data': [-359.85,
    -359.85,
    -0.14999999999997726,
    -0.14999999999997726],
   'unit': 'deg'},
  'lat': {'data': [-0.15, 0.15, 0.15, -0.15], 'unit': 'deg'}}}

This is because of the wrapping of the Angle in the init of the class

gammapy/gammapy/modeling/models/spatial.py

Lines 1668 to 1673 in 90459a5

	def __init__(self, coords, norms=None, interp="lin", **kwargs):
	self._coords = coords.copy()
	self._coords["lon"] = Angle(coords.lon).wrap_at(0 * u.deg)
	self._wrap_angle = (coords.lon.max() - coords.lon.min()) / 2
	self._coords["lon"] = Angle(coords.lon).wrap_at(self._wrap_angle)
	self._interp = interp

But: Why are the lon values not getting wrapped in the creation of the first model above?