Frontend telemetry tests failing with timer/timeout issues

[Mosas2000]

Problem

Multiple telemetry-related tests are failing due to timer handling issues.

Affected Tests

telemetry-sink.test.js

• automatically flushes when batch size reached - Infinite loop error (10000 timers)
• retries on failure - Test timeout (10000ms)
• gives up after max retries - Test timeout (10000ms)

telemetry-integration.test.js

• Page view count assertion: expected 0 but received 1

telemetry-vitals.test.js

• returns unknown for undefined vital - expected 'good' but received 'unknown'

Errors

Error: Aborting after running 10000 timers, assuming an infinite loop!
Error: Test timed out in 10000ms.
AssertionError: expected 'unknown' to be 'good'

Solution

• Fix timer mocking in telemetry-sink tests
• Fix test expectations to match actual behavior
• Add proper cleanup in afterEach hooks