Fix installing setup dependencies for bundled installer on newer versions of pip

[ashovlin]

Issue #, if available: CLI-6153

Don't think we have a GitHub issue, but this has been reported on a few Q&A sites:

1. https://askubuntu.com/questions/1513592/installing-aws-cli-v1-on-ubuntu-24-does-not-work-but-works-fine-on-ubuntu-22
2. https://stackoverflow.com/questions/77658049/getting-pip-error-while-installing-aws-cli

Description of changes:

1. When installing the CLI V1 via the bundled installer, we use the --find-links file://{local path} syntax to install the packages from the bundle, rather than PyPI. At some point (not apparent from pip's changelog, still trying to pinpoint), this started throwing ValueError: non-local file URIs are not supported on this platform: 'file://..
   • To address this, I removed the file:// syntax since --find-links can accept local paths (see example 10 on pip install docs).
2. When testing this on 3.12, installing the bundle fails with ModuleNotFoundError: No module named 'setuptools' since it's no longer included by default.
   • To address this, I added setuptools to our BUILDTIME_DEPS that we install first.
   • I struggled to install setuptools from sdist, which looks like it needs to bootstrap itself. I switched to wheels to alleviate this, though just for the BUILDTIME_DEPS to start. Refresh bundled installer to work with modern pip/venv #4756 alluded to this as future work.
3. I also pinned urllib3 for the bundled installer to a version before 2.0.0 (where they started requiring hatchling). We previously pinned colorama for a similar reason.

Testing

Added new GitHub action to test making the bundle and installing it across our usual Python version + OS matrix.

I'll manually test a dry-run through the internal build system.

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 93.39%. Comparing base (5f07db1) to head (8c8f274).
Report is 81 commits behind head on develop.

Additional details and impacted files

@@           Coverage Diff            @@
##           develop    #9420   +/-   ##
========================================
  Coverage    93.39%   93.39%           
========================================
  Files          210      210           
  Lines        16983    16986    +3     
========================================
+ Hits         15861    15864    +3     
  Misses        1122     1122           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.