Fix callhook error in manual mode

Fixes #1586  
Check force manual switch before causing error about it.

acme.sh

@@ -3365,7 +3365,7 @@ _on_issue_success() {
     fi
   fi
 
-  if _hasfield "$Le_Webroot" "$W_DNS"; then
+  if _hasfield "$Le_Webroot" "$W_DNS" && [ -z "$FORCE_DNS_MANUAL" ]; then
     _err "$_DNS_MANUAL_WARN"
   fi