No spans from blog trigger in isolated worker (host or worker)

Here's the repro app: https://github.com/lmolkova/testfuncotel

Environment:
- A .NET 9 RC 2 SDK
- Microsoft.Azure.Functions.Worker.Extensions.Http.AspNetCore at v2.0.0-preview1
- Microsoft.Azure.Functions.Worker.Sdk at v2.0.0-preview1
- Azure Functions Core Tools at v4.0.6280

It has:
- HTTP and blob triggers
- configures otel to collect incoming and outgoing HTTP and function worker sources
- it sends some custom spans from function invocations
- it exports all logs, traces and spans to local aspire dashboard

What I see:

- HTTP trigger works fine: spans and logs are exported as expected
- Blob trigger does not produce any spans from the worker - even custom ones. It produces a bunch spans from the host, but none of them are related to the specific invocation (or not correlated to it)
- It produces logs, which have trace-id, but there is no corresponding trace

Mysteriously, even the custom activity that works perfectly fine in the HTTP trigger becomes `null` inside blob trigger.

It also produces a bunch of host-level storage-polling noise, but I don't see any spans describing the triggered function

Expected:

Blob trigger is reported as a span on the host and custom activity is reported from inside the trigger code.