Signal/Image analysis: fix TypeError when handling nan values if there is no mask

(cherry picked from commit 07813cb)

Author: PierreRaybaut

cdl/core/model/base.py

@@ -1511,7 +1511,10 @@ def get_masked_view(self) -> ma.MaskedArray:
         """
         self.data: np.ndarray
         view = self.data.view(ma.MaskedArray)
-        view.mask = self.maskdata | np.isnan(self.data)
+        if self.maskdata is None:
+            view.mask = np.isnan(self.data)
+        else:
+            view.mask = self.maskdata | np.isnan(self.data)
         return view
 
     def invalidate_maskdata_cache(self) -> None: