[FIX] web: allow user to scroll horizontally

Steps to reproduce:
- create a contact with a very long name
- create a quotation
- in customer, type the first letter of the very long customer's name
- try to use the horizontal scroll bar

Issue:
close window on horizontal scroll

Solution:
Discriminate an horizontal scroll from a vertical scroll
A test has been added as well as the triggerScroll utility function
to allow proper tests when scrolling on elements

opw-2777443

closes odoo/odoo#86088

Signed-off-by: Aaron Bohy (aab) <aab@odoo.com>
Co-authored-by: Iucapad <luvi@odoo.com>