test: [M3-10474] - Fix qemu-reboot-upgrade-notice.spec.ts test failure (#12691)

* remove double `at` in assertion

* Added changeset: Fix `qemu-reboot-upgrade-notice.spec.ts` test failure due to incorrect assertion

---------

Co-authored-by: Banks Nussman <banks@nussman.us>

Author: bnussman-akamai

packages/manager/.changeset/pr-12691-tests-1755096527481.md

@@ -0,0 +1,5 @@
+---
+"@linode/manager": Tests
+---
+
+Fix `qemu-reboot-upgrade-notice.spec.ts` test failure due to incorrect assertion ([#12691](https://github.com/linode/manager/pull/12691))

packages/manager/cypress/e2e/core/notificationsAndEvents/qemu-reboot-upgrade-notice.spec.ts

@@ -86,9 +86,9 @@ describe('QEMU reboot upgrade notification', () => {
     ];
 
     // We use ! since in `LinodeMaintenanceText` the `start_time` is never null.
-    const formattedTime = `at ${formatDate(upcomingMaintenance[0].start_time!, {
+    const formattedTime = formatDate(upcomingMaintenance[0].start_time!, {
       timezone: mockProfile.timezone,
-    })}`;
+    });
 
     const maintenanceTooltipText = `This Linode’s maintenance window opens at ${formattedTime}. For more information, see your open support tickets.`;