[FIX] web: search model: one2many search default labels

When a one2many is used as a search default, its label has to be fetch
via a name_get in order to get a correct display of the facet
corresponding to that field in the search bar. It turns out that the
search model did not wait properly the return of the name_gets before to
start to compute the facets.

closes odoo/odoo#106522

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