Pull Request for Issue #46419.

Summary of Changes

Remove the false flag for "auto" on the setFrom method from PHPMailer in the MailTemplateFactory. This will improve the standard Joomla e-mail deliverability because now the Return-Path, envelope-from and From are aligned.
By default Joomla was setting this "auto" flag to false. Although PHPMailer's default is "true".

The behaviour won't change for reply-to. E-mail clients already use From as the fallback if there is no reply-to set.
Bounces now are sent to the wrong place for instance user@server.com instead of the "from mail" set in the configuration, this fix solves that issue.
With this fix SPF and DMARC domains will now be aligned and with that improve e-mail deliverability.

Testing Instructions

Set your "Mailer" to PHP Mail in Global Configuration -> Server -> Mail -> Mailer
Send an e-mail using the test e-mail from the configuration or do a lost password check.
Check e-mail headers and see that headers don't align.

Actual result BEFORE applying this Pull Request

Return-Path and envelope-from DON'T match the From.

Return-Path: <user1@srv1.example.nl>
    (envelope-from <user1@srv1.example.nl>)
From: Example Name <noreply@domain.nl>

Expected result AFTER applying this Pull Request

Return-Path and envelope-from DO match the From.

Return-Path: <noreply@domain.nl>
(envelope-from <noreply@domain.nl>)
From: Example Name <noreply@domain.nl>

Link to documentations

Please select:

• Documentation link for docs.joomla.org:

• No documentation changes for docs.joomla.org needed

• Pull Request link for manual.joomla.org:

• No documentation changes for manual.joomla.org needed