assimilation interval added to da cycle attributes

ENDA.py

@@ -460,6 +460,7 @@ class cycle:
         self.ncycles = ncycles
         self.time = time
         self.analysis_times = analysis_times
+        self.assimilation_interval = assimilation_interval
         self.initial_state = initial_state
         self.backgrounds = backgrounds
         self.analyses = analyses