When sending the test email of a mass mailing campaign, it might be
observed that the result is different from the final email sent to
customers.
This is because the `body` field of the final mail message is an `Html`
field with options `sanitize_style=True` and `strip_classes=True`. On
the other hand, the `body_html` field the test mail is a simple `Text`
field which is not sanitized.
We sanitize the `body_html` field with similar options.
opw-1820064
Nicolas Martinelli
866b48a267