remove unused code

Author: Zettat123

services/markup/processorhelper.go

@@ -14,9 +14,6 @@ import (
 func ProcessorHelper() *markup.ProcessorHelper {
 	return &markup.ProcessorHelper{
 		IsUsernameMentionable: func(ctx context.Context, username string) bool {
-			if ctx == nil {
-				return false
-			}
 			mentionedUser, err := user.GetUserByName(ctx, username)
 			if err != nil {
 				return false