[FIX] web: repair length field in view list

Underscore method _.each expects an array like object when a "length"
property is present.

This was an issue with a record having a numeric "length" field set to a
non-negative value. When changing a line the change would not appear on
blur.

This issue was fixed with 0e664c9e9 but introduced back with f0e331e00.

opw-691070

Forward-port of 5d17749ff4 which has been
forgotten during previous forward-port.

addons/web/static/src/js/views/list_view.js

@@ -560,11 +560,12 @@ var ListView = View.extend( /** @lends instance.web.ListView# */ {
                 self.records.remove(record);
                 return;
             }
-            _.each(values, function (value, key) {
+            // _.each is broken if a field "length" is present
+            for (var key in values) {
                 if (fields[key] && fields[key].type === 'many2many')
                     record.set(key + '__display', false, {silent: true});
-                record.set(key, value, {silent: true});            
-            });
+                record.set(key, values[key], {silent: true});
+            }
             record.trigger('change', record);
 
             /* When a record is reloaded, there is a rendering lag because of the addition/suppression of