helpers: drop fmt_date iso8601 decoding to unicode - it will always be str

kallithea/lib/helpers.py

@@ -515,8 +515,7 b' def show_id(cs):'
 
 def fmt_date(date):
     if date:
-        return date.strftime("%Y-%m-%d %H:%M:%S").decode('utf-8')
-
+        return date.strftime("%Y-%m-%d %H:%M:%S")
     return ""