Update progress bar for "install pack dependencies"

[shati-patel]

As @adityasharad suggested in #1076 (comment), we can have more granular progress tracking by counting how many packs to install 📦

This sort of works, except we can't set the maxStep until after the user has selected the packs... So for the first step (here) I just stuck with "2" as the max number of steps, which means that the first step takes up a disproportionate amount of space in the progress bar. This looks a bit odd, but I don't think it's a big problem 😅

Checklist

n/a - just a follow-up to #1076!

• CHANGELOG.md has been updated to incorporate all user visible changes made by this pull request.
• Issues have been created for any UI or other user-facing changes made by this pull request.
• If this pull request makes user-facing changes that require documentation changes, the ready-for-doc-review label has been added to this pull request or the corresponding issue.

[aeisenberg]

So for the first step (here) I just stuck with "2" as the max number of steps, which means that the first step takes up a disproportionate amount of space in the progress bar.

There are similar issues with other progress bars, where we don't know the complete number of steps until later on. I don't think that's a problem we need to (or can) fix (at least without a lot of work).

[adityasharad]

The other alternative is adding some progress calls early to "complete" the progress bar once you work out the total number of steps, and then restart the progress bar for the variable steps (e.g. 1/2, 2/2, [work out the total number of steps], 1/total, 2/total, ..., total/total). It looks a bit odd in the UI and is...not really worth it 😆