[FIX] web: autocomplete selection not hidden

Appending the autocomplete selection too close from the input field leads to display (hidden) problem in some cases (Many2one inside modals views, many2one at the end of a form view, etc.)

This is related to rev. e1cde4d038

closes #4268

addons/web/static/src/js/view_form.js

@@ -3736,7 +3736,10 @@ instance.web.form.FieldMany2One = instance.web.form.AbstractField.extend(instanc
             minLength: 0,
             delay: 250,
         });
-        var appendTo = this.$el.parent().parent();
+        var appendTo = this.$el.parents('.oe_view_manager_body, .modal-dialog').last();
+        if (appendTo.length === 0){
+            appendTo = '.oe_application > *';
+        }
         this.$input.autocomplete({
             appendTo: appendTo
         });