BHV-752: Undepress button when hidden.

Issue
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If there is one spottable `moon.Button` in the view and the `tap` event hides this button, when you 5-way select this button (causing it to hide) and programmatically unhide it, the `pressed` state of the button is still active.

Fix
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When a `moon.Button` is hidden, we deactivate the `pressed` state if it is currently in that state.

Enyo-DCO-1.1-Signed-off-by: Aaron Tam <aaron.tam@lge.com>