fix(tests): increase Phase 1 alert firing timeout to 20 minutes

The Thanos Querier API check timed out at 15 minutes — the alert needs
more time to propagate through Prometheus rule evaluation. Increase
Phase 1 to 20 minutes and adjust Phase 2 to 15 minutes (total 35 min
budget, same as the original 30 min single-phase approach but with the
OOM-safe split).

CI run: https://prow.ci.openshift.org/view/gs/test-platform-results/pr-logs/pull/openshift_monitoring-plugin/860/pull-ci-openshift-monitoring-plugin-main-e2e-incidents/2038878665416118272
Classifications: TEST_BUG (Phase 1 timeout too short)
22/23 tests passed — no OOM, fix working.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: DavidRajnoha

web/cypress/e2e/incidents/00.coo_incidents_e2e.cy.ts

@@ -58,8 +58,8 @@ describe('BVT: Incidents - e2e', { tags: ['@smoke', '@slow', '@incidents', '@e2e
       ).then((result) => result.code === 0 && result.stdout.includes(currentAlertName)),
       {
         interval: 30_000,
-        timeout: 15 * 60_000,
-        errorMsg: `Alert ${currentAlertName} not firing on cluster within 15 minutes`,
+        timeout: 20 * 60_000,
+        errorMsg: `Alert ${currentAlertName} not firing on cluster within 20 minutes`,
       }
     );
 
@@ -71,7 +71,7 @@ describe('BVT: Incidents - e2e', { tags: ['@smoke', '@slow', '@incidents', '@e2e
       () => incidentsPage.findIncidentWithAlert(currentAlertName),
       {
         interval: 2 * intervalMs,
-        timeout: 20 * intervalMs,
+        timeout: 15 * intervalMs,
       }
     );