[FIX] web: SampleServer: properly mock unity_web_search_read

Before this commit, many2one values were still returned as pairs
of id and display_name by unity read, whereas they should be
objects with keys id and display_name.

Part-of: odoo/odoo#133617

addons/web/static/src/model/sample_server.js

@@ -608,9 +608,19 @@ export class SampleServer {
         } else {
             result = this._mockWebSearchRead({ ...params, fields });
         }
-        // populate x2many values
+        // populate many2one and x2many values
         for (const fieldName in params.specification) {
             const field = this.data[params.model].fields[fieldName];
+            if (field.type === "many2one") {
+                for (const record of result.records) {
+                    record[fieldName] = record[fieldName]
+                        ? {
+                              id: record[fieldName][0],
+                              display_name: record[fieldName][1],
+                          }
+                        : false;
+                }
+            }
             if (field.type === "one2many" || field.type === "many2many") {
                 const relFields = Object.keys(params.specification[fieldName].fields || {});
                 if (relFields.length) {