[FIX] web: remove the report_layout from studio selectable widgets

Open studio to modify the widget displaying a relational field.
The report_layout widget can be selected, say, to display payment terms.
Obviously it doesn't make sense.

We remove its supported field, as the field is not generic
(indeed there is only one use for it in the codebase).

opw 1919369

closes odoo/odoo#30303

addons/web/static/src/js/fields/special_fields.js

@@ -122,7 +122,8 @@ var FieldTimezoneMismatch = FieldSelection.extend({
 });
 
 var FieldReportLayout = relational_fields.FieldMany2One.extend({
-    supportedFieldTypes: ['many2one', 'selection'],
+    // this widget is not generic, so we disable its studio use
+    // supportedFieldTypes: ['many2one', 'selection'],
     events: _.extend({}, relational_fields.FieldMany2One.prototype.events, {
         'click img': '_onImgClicked',
     }),