✨ [New]: add `.Select(...)` operation on the `ServiceBusMessageFilter` on the Azure Service Bus queue/topic test fixtures

### Description

During verification of send Azure Service Bus messages, testers often want to inspect the message body and not only the application properties. This is a very common practice and currently is not part of the fluent API interface, which means that it breaks the structure. Especially in polling expressions, testers want to use the `Poll.Until(...)` operation on the message body type.

### Solution

Provides a `.Select(...)` operation on the `ServiceBusMessageFilter` so that we can project the messages.

### Additional context

_No response_