Camera: Disable flash for AE-Bracket

The main flash is high, AE bracketing requires several frames.
If the LED lit up at high for long, it could be burned and cause
HW damge.

Fix: Flash has been disabled if AE-Bracket option is enabled with
proper toast message.

CRs-Fixed: 663613
Change-Id: Ic568630783309af19f7670aee563cd6eb0032fb1
3 files changed