Improve cypress logging output (#10845)

... by grouping together the output from some custom commands.

cypress/support/log.ts

@@ -0,0 +1,45 @@
+/*
+Copyright 2023 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+/// <reference types="cypress" />
+
+declare global {
+    // eslint-disable-next-line @typescript-eslint/no-namespace
+    namespace Cypress {
+        // secret undocumented options to Cypress.log
+        interface LogConfig {
+            /** begin a new log group; remember to match with `groupEnd` */
+            groupStart: boolean;
+
+            /** end a log group that was previously started with `groupStart` */
+            groupEnd: boolean;
+
+            /** suppress regular output: useful for closing a log group without writing another log line */
+            emitOnly: boolean;
+        }
+    }
+}
+
+/** collapse the last open log group in the Cypress UI
+ *
+ * Credit to https://j1000.github.io/blog/2022/10/27/enhanced_cypress_logging.html
+ */
+export function collapseLastLogGroup() {
+    const openExpanders = window.top.document.getElementsByClassName("command-expander-is-open");
+    const numExpanders = openExpanders.length;
+    const el = openExpanders[numExpanders - 1];
+    if (el) el.parentElement.click();
+}