h52nx: if valid_camera_names is None then consider the given camera as valid

nxtomomill/converter/hdf5/acquisition/standardacquisition.py

@@ -417,6 +417,8 @@ class StandardAcquisition(BaseAcquisition):
 
     def camera_is_valid(self, det_name):
         assert isinstance(det_name, str)
+        if self.configuration.valid_camera_names is None:
+            return True
         for vcm in self.configuration.valid_camera_names:
             if fnmatch.fnmatch(det_name, vcm):
                 return True