bz2 suffixes being used despite registry not having bz2 files

[benmoss]

Checklist

• I added a descriptive title
• I searched open reports and couldn't find a duplicate

What happened?

Using the --update flag seems to result in all of my packages that have .conda suffixes being replaced with .tar.bz2 suffixes. It seems to because of this line.

I took a look at fixing it but it seems like the overall strategy being used here of running conda list --json won't work since it doesn't give us the remote URL and so we're forced to re-assemble it from the channel and guess at what the extension is.

[maresb]

Ooh, that's quite nasty. Thanks for tracking down the cause! Unfortunately I don't have any particular ideas about how to fix this, but I'm open to suggestions.