[rush] upgrade-interactive startup can be slow

[elliot-nelson]

Summary

When launching rush upgrade-interactive in a large monorepo on an older MacBook, it took about 15 seconds for the CLI interface to come up.

I was observing via screenshare and the (first-time) user started pressing random keys about 3 seconds in, so I think that's the soft limit for "no output" while loading.

Repro steps

Run upgrade-interactive in a large repo (unclear what that means -- total number of packages, total number of projects, etc.). This particular repo is ~89 projects, ~2700 deps (as reported by rush install).

Details

I think upgrade-interactive can take any amount of time it needs, as long as there's some kind of interactive progress bar, loading spinner, or other output so the user doesn't start spamming ENTERs and CTRL+Cs.

Standard questions

Please answer these questions to help us investigate your issue more quickly:

Question	Answer
@microsoft/rush globally installed version?
rushVersion from rush.json?
useWorkspaces from rush.json?
Operating system?
Would you consider contributing a PR?
Node.js version (node -v)?

[iclanton]

@TheLarkInn - Care to take look at this?