BHV-2446: Reverting change made for BHV-728 in favor of more localized fix.

Issue
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Making the `onSpotlightContainerLeave` event only dispatch when focus had actually left the container breaks functionality in `moon.Panels` as `moon.Panels` handles the leaving of a panel on its own via this event.

Fix
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We revert the original change and move the fix to `moon.Scroller` where the original issue that prompted this fix had been occurring.

Enyo-DCO-1.1-Signed-off-by: Aaron Tam <aaron.tam@lge.com>