use debian11-small and install UV

[kevinAlbs]

Summary

Switch testazurekms-task from debian11-latest-small to debian11-small to fix set-up failure.

Tested with this patch build: https://spruce.mongodb.com/version/690221a09c315e0007b2bcd1

Background & Motivation

#2127 switched the testazurekms-task from debian11-small to debian11-latest-small. The az tool is too old on the debian11-latest-small, triggering a failure (example):

Detected az version 2.18.0 but need version >= 2.25.0

Upgrading az is requested in DEVPROD-23011. This PR proposes reverting to debian11-small and restoring the UV install scripts removed in #2127 in the short term. A newer az is also needed for Azure testing for OIDC.

[eramongodb]

The debian11 distro provides a python3 system binary with virtualenv support.

Instead of restoring old install scripts, suggest implementing the following testazurekms-task-specific workaround prior to dependent scripts and commands:

# Temporary workaround for lack of uv on `debian11`.
uv_dir="$(mktemp -d)"
python3 -m virtualenv "${uv_dir:?}"
(. "${uv_dir:?}/bin/activate" && python -m pip install uv)
PATH="${uv_dir:?}/bin:${PATH:-}"

command -V uv # uv is hashed (/tmp/.../bin/uv)
uv --version  # 0.9.5

[kevinAlbs]

Updated (and thank you for the much simpler suggestion!).

[eramongodb]

Minor suggestion; otherwise, LGTM.