[v12.x] backport npm updates and macOS notarization
This PR backports the updates of npm to v6.14.4 as well as the build commits to enable 10.15 notarization
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
This PR backports the updates of npm to v6.14.4 as well as the build commits to enable 10.15 notarization