[FIX] web: action service: sanitize action.domain

When it is unset, the domain of an action can be either false or
the empty string, which in both cases means []. Before this commit,
we didn't process the domain in thoses cases (i.e. we kept the
false or empty string value). However, having an empty string as
domain could cause issues if it is manipulated by Domain/pyutils.
In particular, in stock.picking, clicking on "Insert menu in
spreadsheet" crashed before this commit.

To prevent those issues from happening, this commit sanitizes the
domain of the action at the first entry point, such that it's
always an array (the empty array in our case).

This commit comes with a test in enterprise, which reproduces the
scenario given above, as we couldn't find framework and blackbox
scenario to highlight it.

closes odoo/odoo#135369

X-original-commit: 0fde590b
Related: odoo/enterprise#47363
Signed-off-by: Samuel Degueldre (sad) <sad@odoo.com>
Signed-off-by: Aaron Bohy (aab) <aab@odoo.com>