prefer system install of UCX in pip devcontainers, update outdated RA…

…PIDS references (#6149)

Contributes to rapidsai/build-planning#118

Proposes the following changes for pip devcontainers:

* prefer system installation of ucx to the one provided by the `libucx-cu{11,12}` wheels (ref: rapidsai/devcontainers#421 (comment))

And some other related changes noticed while doing that:

* update lingering `24.*` references to `25.02`

## Notes for Reviewers

### How I tested this

Relying on CI for most things. Double-checked that `update-version.sh` would have caught the one lingering `24.12` reference like this:

```shell
./ci/release/update-version.sh '25.02.00'
git grep -E '24\.'
```

Authors:
  - James Lamb (https://github.com/jameslamb)
  - Bradley Dice (https://github.com/bdice)

Approvers:
  - Tim Head (https://github.com/betatim)
  - Bradley Dice (https://github.com/bdice)

URL: #6149

.devcontainer/Dockerfile

@@ -6,6 +6,7 @@ ARG PYTHON_PACKAGE_MANAGER=conda
 FROM ${BASE} as pip-base
 
 ENV DEFAULT_VIRTUAL_ENV=rapids
+ENV RAPIDS_LIBUCX_PREFER_SYSTEM_LIBRARY=true
 
 RUN apt update -y \
  && DEBIAN_FRONTEND=noninteractive apt install -y \