Fix #20991 - use name from app.json if available

[mike-marcacci]

Fix#20991 - use name from app.json if available, instead of using package.json.

Test Plan:

I haven't tested my plan 😬but didn't want to file a trivial, low-priority issue here without a PR, since those just take up space!

Release Notes:

[CLI] [ENHANCEMENT] [react-native-git-upgrade] - Use name from app.json if available

[hramos]

Looks fine. I'd still like to see a test plan, to make sure this has at least been tested and verified before merging.

This only touches the upgrade CLI, which is not used at Facebook, so any of our contributors should feel free to land this if they approve of the PR.

[mike-marcacci]

OK, FWIW I used this change when upgrading @boltline/boltline-native. Upgrading ran into another unrelated issue but the name was no longer a problem. Let me know if anyone has a programatic test strategy you'd like implemented here.

[mikemorris]

This looks like a good fix to me, only caution is that IIRC iOS preserves AppName app names throughout, while Android downcases to appname when creating directory paths, would want to double-check that behavior stays consistent.

[facebook-github-bot]

@hramos is landing this pull request. If you are a Facebook employee, you can view this diff on Phabricator.

[react-native-bot]

@mike-marcacci merged commit f59d79c into facebook:master.