When repodata is corrupted, throw it away and download from scratch

[wolfv]

Checks

• I have checked that this issue has not already been reported.

• I have confirmed this bug exists on the latest version of pixi, using pixi --version.

Reproducible example

For some reason, a user reported that their repodata was corrupted:

[it4i-berceanu@login1.karolina ~]$ pixi global install nvim
  × failed to fetch repodata from channels
  ╰─▶ expected `,` or `}` at line 2590828 column 25

Issue description

Repodata is corrupted and pixi crashes

Expected behavior

We should throw away the cached repodata and redownload from scratch. Manually removing the cache helped the user.