Changing the from/sender address in a Compose Scenario

Hi everyone!

Based on a response from the Outlook Add-ins Team - MSFT:
https://stackoverflow.com/a/67630922/833060

Our customers use different shared email addresses to communicate with different clients. With the current outlook-web-addins API we can warn them if they use an unusual sender address for a given message body or recipient address. But we cannot automatically suggest the most likely sender address when they reply to an email. For the recipients, e.g. the `to` address, we can just invoke:

Office.context.mailbox.item.to.setAsync(
[
  {
    displayName: "Allie Bellew",
    emailAddress: "allieb@contoso.com"
  }
], result => console.log(result));

But the same is not possible for the `From` field. Since in Outlook Web they can pretty much set the sender to an arbitrary value, so long as the mail server will accept it, we propose to expose this functionality in the API as well.

Thank you for your response and all the best,
Pascal