Skip the logo markup when a brand or supplier has none

[boo-code]

Questions	Answers
Description?	The brand and supplier listing miniatures read image.bySize.small_default.url unconditionally. Since PrestaShop/PrestaShop#41699 landed in core, ManufacturerLazyArray::getImage() and SupplierLazyArray::getImage() return null when no logo file exists, so on /brands and /suppliers every logo-less entity now dereferences null three times over. The <source> lines were already guarded with !empty; only the <img src> was not. This wraps the <picture> in the same guard, so an entity without a logo renders no image markup instead of a broken one. Its name is still shown, linked, by the brand-infos / supplier-infos block right below.
Type?	bug fix
BC breaks?	no
Deprecations?	no
Fixed ticket?	PrestaShop/PrestaShop#41692
Sponsor company	-
How to test?	Create a brand with no logo and open /brands with this theme active. Before this change the page emits Trying to access array offset on value of type null and, because the warning is printed inside the attribute, the tag comes out as src="<br /><b>Warning</b>: ..."; with warnings off it is src="", which the browser resolves as a second request for the page itself. After the change there is no image element and no warning, and brands that do have a logo are unaffected. Suppliers are the same page-for-page, and note that on a stock install img/su/ has no logo files at all, so /suppliers reproduces it for every row once PS_DISPLAY_SUPPLIERS is on.

Measured on a 9.2.0 shop with this theme active, counting the warning in the rendered HTML:

/brands      3 warnings -> 0     (one logo-less brand; the two with a logo still render theirs)
/suppliers   6 warnings -> 0     (two logo-less suppliers, three null offsets each)

Three warnings per row is the whole chain being walked on null: image['bySize'], then ['small_default'], then ['url'].

One choice worth naming, since it is a judgement call rather than a forced one. When there is no logo I render nothing in the image slot, keeping the surrounding brand-img / supplier-img container so the grid does not reflow. The alternative would be a text fallback inside that slot, which is what the Hummingbird product page does - but on this listing the name is already immediately below in brand-infos, so it would print twice. If you would rather have the placeholder image back for logo-less rows, that is a one-line change to the same guard and I will redo it.

[ps-jarvis]

Hello @boo-code!

This is your first pull request on classic-theme repository of the PrestaShop project.

Thank you, and welcome to this Open Source community!