Fix WindowsCI (again)

[lurch]

Use newer version of ninja

bb5b5f9 failed on Windows CI with:

 - ninja - A newer version of ninja (v1.12.1) is already installed.
 Use --allow-downgrade or --force to attempt to install older versions.
Error: Process completed with exit code 1.

However the preceding commit a5ba689 passed Windows CI just fine.

A bit of investigation reveals that the passing commit used GitHub runner image https://github.com/actions/runner-images/blob/win22/20250309.1/images/windows/Windows2022-Readme.md (which doesn't have ninja pre-installed) whereas the failing commit used GitHub runner image https://github.com/actions/runner-images/blob/win22/20250324.3/images/windows/Windows2022-Readme.md which has Ninja 1.12.1 pre-installed.

I don't think that we can assume that ninja is pre-installed on all GiitHub runner images yet, so rather than removing it from choco_packages.config (i.e. similar to what was done in #2241 ), just update the ninja install to a matching version instead, to hopefully suppress the "A newer version of ninja is already installed" error.

[will-v-pi]

LGTM - and the fix for the next breakage when they eventually bump Ninja again will be removing it from the choco_packages, as by that point all runners will be on a version with Ninja pre-installed

[kilograham]

can we just not use "latest"

[will-v-pi]

can we just not use "latest"

Yeah, we could just delete the version option, instead of updating it to 1.12.1 - although probably still sensible to delete the Ninja entry once it's in the Windows runners by default (like the CMake entry has been deleted)

[lurch]

I'm not a Windows user, so I've never used choco_packages.config (and therefore I'm unable to test). @will-v-pi Feel free to close this PR and replace it with an alternative one. 🪟 🪟