GH-1339: Fix RLErrorHandler with Conversion Ex.

[garyrussell]

Resolves #1339

Error handler was not called for conversion exceptions, preventing
the application frm returning some error to the caller for request/reply
processing.

cherry-pick to 2.2.x

[artembilan]

... and cherry-picked to 2.2.x

[ThomHurks]

We just updated to Spring Boot 2.4.7 and tests started to fail related to AMQP. It seems some tests where we expect ListenerExecutionFailedException to be thrown it now throws for MessageConversionException. Looking at the changelog it’s likely caused by this change. Doesn’t that mean this is kind of a breaking change in a patch release? It surprised us at least. We can change the tests to expect a different exception, but didn’t yet verify if this affects runtime behavior in any way.

[garyrussell]

Can you provide an example of such a test? Previously, MessageConversionException were thrown to the listener container and bypassed the listener error handler (if one was provided).

I don't see how a LEFE can now become a MCE; l must be missing something in your description.

I do see how an MCE will now be thrown as an LEFE wrapping it, however; so perhaps that's what you meant.

While technically a breaking change; we don't expect user code to be calling the listener adapter directly, but I do see that it could break some test cases if you are testing a listener directly. Sorry for the inconvenience. We should have unwrapped it for MCEs, to retain existing behavior, but I am not sure I want to make another "breaking" change in the next patch release.