Summary:
This diff switches LogBox over to use a Modal component so that the log inspector is always full screen.
In order to do that, it needed to add an `internal_excludeLogBox` flag to AppContainer so that it's not recursively rendered as: AppContainer -> LogBox -> Modal -> AppContainer. Not thrilled about the prop but it's necessary for now until this is rendered as it's own root (which we're working on next).
Changelog: [Internal]
Reviewed By: rubennorte
Differential Revision: D18461394
fbshipit-source-id: e1a80dfffbbe6c5467ac6f8d3c445a3280829020
a64e5bc251