hide RAFT #pragma deprecation warnings

[trxcllnt]

Define -DRAFT_HIDE_DEPRECATION_WARNINGS added in rapidsai/raft#2271.

[trxcllnt]

Seems like raft headers have code that triggers warnings. Since the pip builds add raft as a CMake submodule, the raft includes are added as -I instead of -isystem, so raft warnings are failing the -Werror cuvs build.

Doesn't raft build with -Werror? It seems like any raft warnings should have been caught in the raft CI before being merged?

[cjnolet]

/merge