Clarify support for Transactional Producer API

[chuck-alt-delete]

Through some testing and reading other issues posted, it seems like Azure EventHubs does not support the transactional producer API -- it fails to provide a producer ID when a transaction is initiated. It would be helpful if the README and/or Azure documentation would clarify this as a limitation and perhaps also whether this is under active development or not currently roadmapped.

[habibur4340]

@chuck-alt-delete
Acknowledging Azure EventHubs' lack of transactional producer API support is crucial. Clarifying this limitation in the README and Azure documentation, along with any development plans, would help users. For comprehensive API management and testing, consider using Apidog to supplement documentation and testing needs, especially given EventHubs' current constraints.