feat(core): Add spanExceptionsIntegration to capture exceptions recorded on spans - #26115

Why: With enableOpenTelemetrySetup: true, OpenTelemetry instrumentation records errors through span.recordException(), which is a no-op on Sentry spans, so those errors never reach Sentry. spanExceptionsIntegration() captures them, linked to the span; it's opt-in because instrumentation also records errors the app handles, which is why #11221 removed the span processor version.

How to review: Start with packages/core/src/integrations/spanExceptions.ts and the recordException hook both span classes now emit; the rest is re-exports. It skips exceptions recorded while tracing is suppressed and captures with tracing suppressed, so the SDK's own failing requests or I/O in beforeSend can't loop back into it.

Unsure about:

• The name, proposed in Capture exceptions from OpenTelemetry span events #16015 and easy to change.
• If a span records an error before an SDK handler captures the same object, the first event, with this integration's handled: true mechanism, is the one kept.
• BullMQ forwards retried Redis and lock errors to recordException(), so those are captured too, and a job that then fails is also reported as job failed.
• Only the SDK's suppressTracing() is honored, not OpenTelemetry's own suppression key, because core can't read the OpenTelemetry context.

Closes #16015