Support uAMQP unit tests when RTTI is disabled

## Summary
The uAMQP claim-based security unit test uses `dynamic_cast` while handling `Azure::Core::RequestFailedException`. The cast has no RTTI guard.

## Motivation
The default Rust AMQP build excludes the uAMQP test block. A uAMQP unit test build with RTTI disabled can fail to compile or emit MSVC warning C4541. The problem exists on `main` and was not introduced by pull request #7400.

## Proposal
Replace the RTTI-dependent exception inspection with a nested rethrow and typed catch, or guard the test consistently. Add validation for the uAMQP unit test configuration with RTTI disabled.

Found while reviewing #7400.

Start with the uAMQP claim-based security unit test and trace its handling of Azure::Core::RequestFailedException, including the dynamic_cast. Replace or guard the RTTI-dependent inspection as proposed, then validate the uAMQP unit-test configuration with RTTI disabled and confirm it compiles without MSVC warning C4541.

Written by the indexing model from the issue text.