Summary:
Update LogBox on iOS to lazily initialize, using a synchronous RCTSurface, behind RCTSharedApplication checks.
This results in faster of LogBox, without keeping around a long lived window in the background, and only used when LogBox is used.
On Android, we still start the react app in the background but we create a dialog when it's shown and then destroy it when it's hidden. Once we have the sync APIs on android we can update it to use the same strategy.
Changelog: [Internal]
Reviewed By: fkgozali
Differential Revision: D18925538
fbshipit-source-id: 1a72c39aa0fc26c8ba657d36c7fa7bc0ae777eb9