fix(test/subscription): restore timing normalization (I3)
empty_stream_advisories and unreachable_endpoint_network_error tests were missing normalize_timing wrapper around render_report_to_string calls, causing timing-flaky snapshots to fail Phase 4 regression checks.
Restore normalize_timing wrapping to use canonical XXms placeholder in snapshots.
Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>
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