remove mean sustraction in integration

that was a quick hack that should not be done, background subtraction is
the way to go.

src/toolbox_scs/detectors/hrixs.py

@@ -257,7 +257,6 @@ def parabola(x, a, b, c=0):
 
 
 def integrate(image, factor=FACTOR, range=RANGE, curvature=(CURVE_A, CURVE_B), ):
-    image = image - image.mean()
     x = np.arange(image.shape[1])[None, :]
     y = np.arange(image.shape[0])[:, None]
     ys = factor * (y - parabola(x, curvature[1], curvature[0]))