Scenario:
- add a file in mass mailing editor => an generic icon (instead of lower
version where icon depended on mimetype) is added linking the file
- save and send mail => no icon is shown in email received
The system is targeting `a[href*="/web/content/"][data-mimetype]:empty`
to add real image inside instead of using background-image attribute
which is stripped in sanitized.
With this commit, data-mimetype is not removed when image processing
attributes are removed when a file is inserted.
opw-2474053
closesodoo/odoo#70022
X-original-commit: eb3772508ce518ff3f84724eebbe43fd1e040d77
Signed-off-by: Nicolas Lempereur (nle) <nle@odoo.com>