[FIX] *: adapt front-end HTML field sanitization

*: account, event_booth, gamification, hr, project,
   website_event_track, website_hr_recruitment, website_slides

HTML fields that appear in the front-end can be modified using the
website editor. Some of them are sanitized in a way that breaks the
behavior of snippets that can be dropped within them.

This commit adapts the sanitization of those HTML fields so that the
snippets behave as expected.

opw-3267589

closes odoo/odoo#125650

X-original-commit: 477cd32c7924ce79e8f29cf567fbbc625f24534f
Related: odoo/enterprise#42802
Signed-off-by: Romain Derie (rde) <rde@odoo.com>