Email sending tool (#3837)

### What problem does this PR solve?

_Briefly describe what this PR aims to solve. Include background context
that will help reviewers understand the purpose of the PR._
Added the function of sending emails through SMTP
Instructions for use-
Corresponding parameters need to be configured
Need to output upstream in a fixed format

![image](https://github.com/user-attachments/assets/93bc1af7-6d4f-4406-bd1d-bc042535dd82)


### Type of change


- [√] New Feature (non-breaking change which adds functionality)

---------

Co-authored-by: Kevin Hu <kevinhu.sh@gmail.com>

web/src/pages/flow/flow-drawer/index.tsx

@@ -81,6 +81,7 @@ const FormMap = {
   [Operator.Concentrator]: () => <></>,
   [Operator.Note]: () => <></>,
   [Operator.Template]: TemplateForm,
+  [Operator.Email]: EmailForm,
 };
 
 const EmptyContent = () => <div></div>;