test: drain transient STATUS results in errorEventFromServer test

[devin-ai-integration]

Requirements

• I have added test coverage for new or changed functionality
• I have followed the repository's pull request submission guidelines
• I have validated my changes against all supported platform versions

Related issues

• SDK-2111 — Flaky test: FDv2StreamingSynchronizerTest.errorEventFromServer intermittently returns STATUS instead of CHANGE_SET

Describe the solution you've provided

The errorEventFromServer test previously called sync.next() exactly once and asserted the result was CHANGE_SET. Under resource contention (full test suite), the EventSource can experience a transient connection fault before the SSE events arrive, producing a STATUS(INTERRUPTED) that beats the expected CHANGE_SET into the result queue.

The fix replaces the single next() call with a drain loop (up to 10 iterations) that consumes and asserts on transient STATUS results until the expected CHANGE_SET arrives. This mirrors the existing pattern already used by reconnectAfterPartialProtocolSequenceDeliversChangeset in the same test class, and reflects real-world SourceManager behavior which calls next() in a loop.

No production code is changed.

Items for reviewer attention:

• The per-iteration timeout is 5 seconds, but the class-level @Rule Timeout.seconds(10) will kill the test well before 10 × 5s. Verify this interaction is acceptable.
• Consider whether other tests in this file (e.g. heartbeatEvent, shutdownAfterEventReceived) could be similarly flaky and benefit from the same pattern.

Describe alternatives you've considered

• Server-ready synchronization barrier (Option B in the ticket): harder to implement reliably since the flakiness may be caused by thread scheduling delays, not connection failures.
• Suppress transient faults in production handleError() (Option C): inappropriate since the current production behavior of reporting every interruption is correct.

Additional context

The JIRA ticket description was also reformatted (escaped markdown from Cursor was rendering poorly in Jira).

Link to Devin session: https://app.devin.ai/sessions/555f5a4faf774eba9d03b6c61e12402e

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Note

Low Risk
Low risk because changes are confined to a unit/integration test; it only adjusts assertions to tolerate transient STATUS(INTERRUPTED) results that can occur under contention.

Overview
Makes FDv2StreamingSynchronizerTest.errorEventFromServer non-flaky by no longer assuming the first sync.next() result is a CHANGE_SET.

The test now drains up to 10 queued STATUS results (asserting they are STATUS) until the expected CHANGE_SET arrives, then asserts the changeset is present.

^{Written by Cursor Bugbot for commit bb26cd4. This will update automatically on new commits. Configure here.}

[devin-ai-integration]

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