Component: ui, tests

Why this is needed: We're missing a lot of coverage for UI behaviour, making new additions and refactoring harder over time.

What should be done:

• Introduce Cypress integration tests (no deployment required, only mocks)
• Test navigation scenarios (sidebar, selecting table entries, switching between tabs...)
• Test Node deployment scenarios (successful deployment, failed deployment, no Job found)
• Test Alerts scenarios (impact on table cells, Overview tab, Alerts tab)
• Test Creation scenarios (create Volume from Volume page, from Node page, test various error cases, ...)

Maybe some other to be added

Implementation proposal (strongly recommended):
Add a step to run Cypress tests in a UI-dedicated test stage (maybe under unit-tests?), and when applicable, add an E2E variant to these tests to run under multiple-nodes-centos.

Test plan: N/A