[3.9] gh-109002: Ensure only one wheel for each vendored package (GH-109003) (#109008)

[3.9] gh-109002: Ensure only one wheel for each vendored package (GH-109003) (#109008)

Output with one wheel:
```
❯ GITHUB_ACTIONS=true ./Tools/build/verify_ensurepip_wheels.py
Verifying checksum for /Volumes/RAMDisk/cpython/Lib/ensurepip/_bundled/pip-23.2.1-py3-none-any.whl.
Expected digest: 7ccf472345f20d35bdc9d1841ff5f313260c2c33fe417f48c30ac46cccabf5be
Actual digest:   7ccf472345f20d35bdc9d1841ff5f313260c2c33fe417f48c30ac46cccabf5be
::notice file=/Volumes/RAMDisk/cpython/Lib/ensurepip/_bundled/pip-23.2.1-py3-none-any.whl::Successfully verified the checksum of the pip wheel.
```

Output with two wheels:
```
❯ GITHUB_ACTIONS=true ./Tools/build/verify_ensurepip_wheels.py
::error file=/Volumes/RAMDisk/cpython/Lib/ensurepip/_bundled/pip-22.0.4-py3-none-any.whl::Found more than one wheel for package pip.

::error file=/Volumes/RAMDisk/cpython/Lib/ensurepip/_bundled/pip-23.2.1-py3-none-any.whl::Found more than one wheel for package pip.
```

Output without wheels:
```
❯ GITHUB_ACTIONS=true ./Tools/build/verify_ensurepip_wheels.py
::error file=::Could not find a pip wheel on disk.
```
(cherry picked from commit f8a047941f2e4a1848700c21d58a08c9ec6a9c68)

Co-authored-by: Łukasz Langa <lukasz@langa.pl>