Update JS documentation.

1. Clarify that EJs have the same network access as FGS
2. Clarify that jobFinished does not need to be called if onStopJob is called

Bug: 19536175
Bug: 171305774
Test: N/A
Change-Id: I72732c860c95ce6f4b8b8343b5b51dc49a917fee
3 files changed