BHV-10787: Capture Spotlight focus in fullscreen mode.

Issue
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Upon initially changing to fullscreen video mode, when the pointer timed out and hid, the controls and/or banner cannot be brought back via the 5-way up/down keys.

Fix
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We capture the `onSpotlightFocus` event via the capture API to constrain Spotlight focus to the `moon.VideoPlayer` in fullscreen mode.

Enyo-DCO-1.1-Signed-off-by: Aaron Tam <aaron.tam@lge.com>