Disable storing sent message on IMAP when SMTP server does this automatically

Expected behavior

Have only 1 copy of sent messages

Actual behavior

There is 2 copies of sent messages

This is not exactly problem of the Mail app.
This exact problem is presented on a lot of mail clients (thunderbird, mailspring)
On thunderbird can be solved by Disabling to keep a copy of sent message to Sent folder.

I think what is happening is.
You send a message, mailApp puts a copy on Sent folder
Outlook server ALSO places a copy on Sent folder after forwarding the message
Local copy synced to server and Server copy synced to Local
and you end up with 2 sent copies.

So, an option like this will probably fix it.

• Keep a copy of sent message to sent folder

Mail app

Mail app version: 1.9.4

Mailserver or service: Outlook

Server configuration

Operating system: Unraid

Web server: Nginx

Database: PostgreSQL

PHP version: 7.4.15

Nextcloud Version: 20.0.8

Client configuration

Browser: Chrome 89

Operating system: Windows10

No source files, tests, or entry points are named. Start by locating the sent-message handling and settings entry points, then verify the Outlook scenario described in the issue. Done means users can disable keeping a local sent-message copy so only the server-created copy remains.