BHV-6683: Prevent unnecessary relayout by clipping overflow.

Issue
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`GridListImageItem` propagates a layout change to all its ancestors when it contains a `Marquee`, which can negatively affect performance (to a smaller degree).

Fix
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We set `overflow:hidden` so that a relayout is not run on ancestors of `GridListImageItem`. I'm curious if anything would be taking advantage of the original style `overflow:visible`, though that would seem unlikely as it would result in an odd-looking `GridListImageItem`.

Enyo-DCO-1.1-Signed-off-by: Aaron Tam <aaron.tam@lge.com>