slowmode should properly error out on 7 hours now (#3453)

redbot/core/commands/converter.py

@@ -282,14 +282,15 @@ else:
 
         async def convert(self, ctx: "Context", argument: str) -> timedelta:
             if self.default_unit and argument.isdecimal():
-                delta = timedelta(**{self.default_unit: int(argument)})
-            else:
+                argument = argument + self.default_unit
+
             delta = parse_timedelta(
                 argument,
                 minimum=self.minimum,
                 maximum=self.maximum,
                 allowed_units=self.allowed_units,
             )
+
             if delta is not None:
                 return delta
             raise BadArgument()  # This allows this to be a required argument.