Filter normalization with 0 counts also in no footprint mode

eos/projection.py

@@ -237,7 +237,7 @@ class LZProjection(ProjectionInterface):
 
     def normalize_no_footprint(self, norm: LZNormalisation):
         norm_lz = norm.norm
-        ref_lz = (self.data.I/norm_lz)
+        ref_lz = (self.data.I/np.where(norm_lz>0, norm_lz, np.nan))
         ref_lz *= norm.monitor/self.monitor
         ref_lz[np.logical_not(self.data.mask)] = np.nan
         self.data.norm = norm_lz