[FIX] website: show icons in autocomplete results when no image defined

Since [1] when the search bar was refactored, images can be displayed in
the autocomplete results, and fallback icons are displayed instead of
images for records that have no images.
However, if no module that participates in the results provides actual
images, then the fallback icons are not displayed at all.

This commit makes the fallback icons displayed only based on the "Image"
toggle option of the search bar.
It also disables the hidden display options and enables the visible
ones.

Steps to reproduce:
- Do NOT install website_sale (which is currently the only module that
provides autocomplete results with images).
- Drop a "Search" block.
- Save.
- Type a single letter in the search box. (e.g. "a")
=> Autocomplete results were displayed without their icons.

[1]: https://github.com/odoo/odoo/commit/7559626c54e34b41e1549e28276a650accec6986



task-2951026

closes odoo/odoo#98241

Signed-off-by: Romain Derie (rde) <rde@odoo.com>