fix: clear warning state on Decimal.parse error

Explicitly call hide_amount_warning when Decimal.parse returns error.

lib/mv_web/live/membership_fee_type_live/form.ex

@@ -414,7 +414,7 @@ defmodule MvWeb.MembershipFeeTypeLive.Form do
         end
 
       :error ->
-        socket
+        hide_amount_warning(socket)
     end
   end