fix ism e2e: dismissToast and failOnStatusCode for managed service

[aditi-1601]

Description

Fix ISM E2E Cypress tests. Toast notifications from ISM job interval/jitter updates block UI interactions in managed_indices_spec.js, causing subsequent tests to fail when trying to click elements behind the toast.

Testing

Ran managed_indices_spec.js locally against OpenSearch 2.13.0 with ISM plugin:
Managed indices
can have policies removed
✓ successfully (15014ms)
can have policies retried
✓ successfully (33231ms)
can edit rollover_alias
✓ successfully (6461ms)
can change policies
✓ successfully (15843ms)
can manage data stream indices
✓ successfully (8214ms)

Issues Resolved

[List any issues this PR will resolve]

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PR Code Suggestions ✨

Explore these optional code suggestions:

Category	Suggestion	Impact
General	Handle multiple toasts in dismiss command When multiple toasts are visible, cy.get with a single selector will fail because it matches multiple elements. Iterate over all close buttons to dismiss every toast reliably, avoiding flaky test failures. cypress/utils/plugins/index-management-dashboards-plugin/commands.js [175-181] Cypress.Commands.add('dismissToast', () => { cy.get('body').then(($body) => { - if ($body.find(`[data-test-subj="toastCloseButton"]`).length) { - cy.get(`[data-test-subj="toastCloseButton"]`).click({ force: true }); + const $buttons = $body.find(`[data-test-subj="toastCloseButton"]`); + if ($buttons.length) { + cy.get(`[data-test-subj="toastCloseButton"]`).each(($el) => { + cy.wrap($el).click({ force: true }); + }); } }); }); Suggestion importance[1-10]: 7 __ Why: Valid improvement: cy.get on a selector matching multiple elements can fail in Cypress when clicking, so iterating with .each() makes the dismissToast command more robust when multiple toasts are visible.	Medium