Report footer is sometimes misplaced in settings preview. We change the css to always stick to the bottom of the preview, no matter the content height. Task-3145445 closes odoo/odoo#136534 X-original-commit: 9be75bb17063c6b0207aa82144e9f44b6e49dc45 Signed-off-by: David Monjoie (dmo) <dmo@odoo.com>