Use `rapids-init-pip` in `pip`-based CI scripts

[jameslamb]

Description

rapidsai/gha-tools#180 introduced a new tool in gha-tools, rapids-init-pip, which does the following:

• ensures that environment variable PIP_CONSTRAINT is set
• ensures that the file it points to exists
• does not modify PIP_CONSTRAINT if it is already set

This allows CI scripts to unconditionally refer to PIP_CONSTRAINT.
That should reduce the diversity of approaches to "constrain what pip installs" in RAPIDS CI, which should make it easier to modify that for exercises like "use wheels from this cuvs PR over in CI on this cuml PR".

This issue documents the work of rolling out use of that tool across RAPIDS.

Benefits of this work

• makes use-artifacts-from-other-PRs-in-CI easier
• provides a standardized target for other efforts to constraint what pip installs (e.g. Testing against oldest python dependencies  #81)

Acceptance Criteria

• across RAPIDS, all CI scripts using pip to install packages (e.g. ci/build_wheel_*.sh, ci/test_wheel_*.sh):
  • call source rapids-init-pip
  • include --constraint "${PIP_CONSTRAINT} if there are any other uses of --constraint
  • append to, instead of overwriting, the file pointed to by ${PIP_CONSTRAINT}

Approach

Ensure this list includes all repos we want to update:

• cucim (use 'rapids-init-pip' in wheel CI, other CI changes cucim#881)
• cudf (use 'rapids-init-pip' in wheel CI, other CI changes cudf#18902)
• cugraph (use 'rapids-init-pip' in wheel CI, other CI changes cugraph#5089)
• cugraph-gnn (use 'rapids-init-pip' in wheel CI, other CI changes cugraph-gnn#212)
• cuml (use 'rapids-init-pip' in wheel CI, other CI changes cuml#6779)
• cuopt (https://github.com/rapidsai/cuopt/pull/2503)
• cuvs (use 'rapids-init-pip' in wheel CI, other CI changes cuvs#917)
• cuxfilter (use 'rapids-init-pip' in wheel CI, other CI changes cuxfilter#690)
• dask-cuda (use 'rapids-init-pip' in wheel CI, other CI changes dask-cuda#1496)
• jupyterlab-nvdashboard (use 'rapids-init-pip' in wheel CI, other CI changes jupyterlab-nvdashboard#235)
• kvikio (use 'rapids-init-pip' in wheel CI, other CI changes kvikio#725)
• nx-cugraph (use 'rapids-init-pip' in wheel CI, other CI changes nx-cugraph#141)
• pynvjitlink (no changes required - didn't seem worth it to put up a PR there just for this, since that doesn't depend on any other RAPIDS libraries)
• raft (use 'rapids-init-pip' in wheel CI, other CI changes raft#2677)
• rapids-build-backend (no changes required - didn't seem worth it to put up a PR there just for this, since that doesn't depend on any other RAPIDS libraries)
• rapids-dask-dependency (use 'rapids-init-pip' in wheel CI, other CI changes rapids-dask-dependency#104)
• rapids-logger (use 'rapids-init-pip' in wheel CI, other CI change rapids-logger#39)
• rapidsmpf (feat: add wheel build of rapidsmpf rapidsmpf#269 (comment))
• rmm (use 'rapids-init-pip' in wheel CI, other CI changes rmm#1926)
• ucx-py (use 'rapids-init-pip' in wheel CI, other CI changes ucx-py#1136)
• ucxx (use 'rapids-init-pip' in wheel CI, other CI changes ucxx#421)

And roll out these changes to all those repos.

Notes

This is a small change... to save CI resources and reviewer time, consider batching it up together with other small, touch-a-lot-of-repos changes like #178