Export ucx dependency

[vyasr]

Once openucx/ucx#9614 is resolved we should revert #172 and #175.

[pentschev]

Those changes probably won't make their way in until UCX 1.17.x, maybe 1.16.x but I'll have to check when we get the fix merged.

[vyasr]

Fix was merged and backported to 1.16.x, so we can rely on it in ucxx after 1.16 is released and we bump to building against that.

[jameslamb]

Noting here that if/when we make that change, it could simplify raft-dask too:

https://github.com/rapidsai/raft/blob/3720d8e91c21ec95d3dbe8e0d1a4515eb60fa7fa/python/raft-dask/CMakeLists.txt#L33-L35