Fix scope and path names for publish pipeline

[amgleitman]

Please select one of the following

• I am removing an existing difference between facebook/react-native and microsoft/react-native-macos 👍
• I am cherry-picking a change from Facebook's react-native into microsoft/react-native-macos 👍
• I am making a fix / change for the macOS implementation of react-native
• I am making a change required for Microsoft usage of react-native

Summary

This is a follow-up to #1919 and addresses three things:

• Change some display names in our beachball publish pipeline so they line up with their newly generalized roles.
• Remove packages/react-native from the beachball publish scope so we don't try to publish it from the main branch. (Note that the beachball publish pipeline only gets run from the main branch.)
• Be explicit about the local file path that we publish react-native-macos from. (For some strange reason, npm was trying to interpret the original as a GitHub username and repository.)

Changelog

[INTERNAL] [FIXED] - More pipeline fixes

Test Plan

Running npm publish packages/react-native --dry-run locally results in this weird error:

npm ERR! code 128
npm ERR! An unknown git error occurred
npm ERR! command git --no-replace-objects ls-remote ssh://git@github.com/packages/react-native.git
npm ERR! git@github.com: Permission denied (publickey).
npm ERR! fatal: Could not read from remote repository.
npm ERR!
npm ERR! Please make sure you have the correct access rights
npm ERR! and the repository exists.

Running npm publish ./packages/react-native --dry-run locally results in this, which is closer to what we want:

...
npm WARN This command requires you to be logged in to https://registry.npmjs.org/ (dry-run)
npm notice Publishing to https://registry.npmjs.org/ (dry-run)
...