[FIX] link_tracker: Filter by tracked URL code is not working

When trying to filter links by a tracked URL code, the following warning
is shown:

    WARNING dbname odoo.models: Cannot execute name_search, no _rec_name
	defined on link.tracker.code

and the applied filter gives all records.

closes odoo/odoo#71376

X-original-commit: 3687dabbc373e57e24ca4596c18ef1dacfde8273
Signed-off-by: agr-odoo <agr-odoo@users.noreply.github.com>

addons/link_tracker/models/link_tracker.py

@@ -196,6 +196,7 @@ class LinkTracker(models.Model):
 class LinkTrackerCode(models.Model):
     _name = "link.tracker.code"
     _description = "Link Tracker Code"
+    _rec_name = 'code'
 
     code = fields.Char(string='Short URL Code', required=True, store=True)
     link_id = fields.Many2one('link.tracker', 'Link', required=True, ondelete='cascade')