chore(ci): fix npm cache path for windows; remove the whole cache fol…

[gribnoysup]

After I re-enabled the npm ls check in #6644 some windows tasks started flaking a lot during the install due to npm failing to cleanup some deps on install and then failing because those are erraneous (it's not a new thing, just the check was skipped before):

[2025/01/24 09:38:34.465] npm WARN cleanup Failed to remove some directories [
[2025/01/24 09:38:34.465] npm WARN cleanup   [
[2025/01/24 09:38:34.465] npm WARN cleanup     'Z:\\data\\mci\\da882451ded25a5d9be4a843af055dab\\src\\node_modules\\appdmg',
[2025/01/24 09:38:34.465] npm WARN cleanup     [Error: EPERM: operation not permitted, rmdir 

...

[2025/01/24 09:38:39.709] npm ERR! invalid: appdmg@ Z:\data\mci\da882451ded25a5d9be4a843af055dab\src\node_modules\appdmg

I'm not exactly sure what's going on here, but internet seems to mention that EPERM on windows with npm usually is caused by cache being in a weird state and I noticed that our npm_config_cache is not set correctly on windows:

[2025/01/24 09:31:28.402] cache = "Z:\\cygdrive\\z\\data\\mci\\da882451ded25a5d9be4a843af055dab\\src\\.deps\\.npm"

I fixed the path. Also changed a bit how we clean up the cache: npm cache clean is deprecated, you can pass the --force flag but I thought nuking the whole folder should be even better (and it gets rid of a warning being printed).

Did a few manual patches and the task seems to be passing for me, hopefully this deals with the flake, worst case scenario it fixes the wrong npm cache path we have right now 🙂