This commit fixes the size of an image being set with
a 0 when it was given using the 'size' option.
In legacy, when 0 was given to one of the parameters,
it was simply ignored and not set on the image. Since
the fields has been converted, it was set and the image
was not visible, because of an height/width equal to 0.
A test has been added to assert this behavior.
closesodoo/odoo#99613
Signed-off-by: Simon Genin (ges@odoo) <ges@odoo.com>