[CI] unpin cmake in ci and devcontainer

[marcalff]

See related:

• #3334
• #3336

Now that github downgraded the CMake version from 4.0 in the affected images, the work around to pin cmake to 3.31.6 is no longer needed.

Please do a partial rollback only:

• do not invoke setup_cmake from workflow/ci.yml
• preserve the setup_cmake scripts in ci

We might need the scripts again later.