Include opened state in the counts for epics

ee/app/finders/epics_finder.rb

@@ -19,9 +19,12 @@ class EpicsFinder < IssuableFinder
     execute.count
   end
 
-  # we don't have states for epics for now but need this method
+  # we don't have states for epics for now but need counts for all and opened
   def count_by_state
-    { all: row_count }
+    {
+      all: row_count,
+      opened: row_count
+    }
   end
 
   def group