Support in `registerListener()` to handle listening on own `UUri`

I think in `registerListener()` we should be explicitly handling things differently depending on whether the `UUri` we're given describes a RPC Request or a Response.

If you'd like, you can take a look at how this is done in [`up-client-zenoh-rust`](https://github.com/eclipse-uprotocol/up-client-zenoh-rust/blob/dc0a3a95564ab1c83771fe71f0da5a261d469fb6/src/utransport.rs#L537)

Note the Response message section on #38. I thought it a good idea how in the Rust implementation we ensure that we have a Response callback registered.

Start by reading the C++ registerListener() implementation and the Response message discussion in issue #38. Compare its behavior with the Response handling in up-client-zenoh-rust/src/utransport.rs around line 537, then verify that Request and Response UUri registrations each receive the intended callback behavior.

Written by the indexing model from the issue text.