Remove ucx-proc conda dependency

[jameslamb]

Description

It should be possible for RAPIDS projects to stop depending on the ucx-proc package from conda-forge.

The package no longer has a corresponding feedstock building it... it was removed in conda-forge/ucx-split-feedstock#111. See @pentschev 's comments in rapidsai/ucxx#280 (comment)

One thing you don't need to do anymore is provide ucx-proc==cpu, conda-forge/ucx-split-feedstock#111, which is determined at runtime.*

The minimum UCX version RAPIDS supports today is 1.15.0 (code link), so it's safe to make this change.

Benefits of this work

• faster conda solves
• reduces risk of conflicts in environment solves

Acceptance Criteria

• no RAPIDS projects have direct dependencies on ucx-proc packages

Approach

Search for references via https://github.com/search?q=org%3Arapidsai%20%22ucx-proc%22%20AND%20NOT%20is%3Aarchived&type=code

Update the task list below and remove those references.

Updates

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1. cugraph (remove ucx-proc dependency cugraph#4894)
2. dask-cuda (remove ucx-proc dependency dask-cuda#1429)
3. dask-build-environment (remove ucx-proc dependency dask-build-environment#109)
4. integration (should be able to remove ucx-proc from the list of package exclusions once it drops out of cuGraph's dependencies ... https://github.com/rapidsai/integration/blob/172ef624ea50670969e1fd79930a46eabdd9c3c9/ci/check_conda_nightly_env.py#L21-L22)