UCT/CUDA_IPC: Detect different PID namespace to avoid non-reachable (#11514)

* UCT/CUDA_IPC: Add fabric flag to cuda address and detect different PID namespace to avoid non-reachable

* UCT/CUDA_IPC: Preserve legacy peer reachability

* UCT/CUDA_IPC: Query fabric support without current context

* UCT/CUDA_IPC: Always pack PID namespace

* UCT/CUDA_IPC: Remove redundant address comment

* UCP/WIREUP: Pass iface address length for aux ep

* UCT/CUDA_IPC: Address fabric support review comments

* UCT/CUDA_IPC: Clean up merge resolution

* UCT/CUDA_IPC: Restore iface address unpack style

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Co-authored-by: shachar hasson <shasson@shasson-mlt.client.nvidia.com>