Always show back button in the right panel (#29128)

* Construct history on setCard

So that back buttons are always shown in the right panel

* Check card state to ensure operation is atomic

* Fix tests

* Fix lint

* Remove null case

* Fix broken test

playwright/e2e/read-receipts/index.ts

@@ -526,9 +526,10 @@ class Helpers {
         await expect(threadPanel).toBeVisible();
         await threadPanel.evaluate(($panel) => {
             const $button = $panel.querySelector<HTMLElement>('[data-testid="base-card-back-button"]');
+            const title = $panel.querySelector<HTMLElement>(".mx_BaseCard_header_title")?.textContent;
             // If the Threads back button is present then click it - the
             // threads button can open either threads list or thread panel
-            if ($button) {
+            if ($button && title !== "Threads") {
                 $button.click();
             }
         });