fix(usePlaybackOptions): clear screen regions when screenRegions is unset

[andriiboliboksc]

What changed

The screenRegions effect bails on any falsy value, so passing undefined never calls setScreenRegions and previously-set regions can't be cleared via the prop.

Drop the falsy guard and coalesce unset → {}. Since setScreenRegions is full-replacement (empty object clears all regions), the hook is now properly declarative: pass regions to set them, omit/undefined to clear.

[msilivonik-sc]

I think treating undefined as empty makes sense for this API, because screenRegions is intended to be a fully declarative prop: the value represents the complete desired region set, so omitting it means no regions should be active.

Also let's update comment of screenRegions here and here:

/**
 * Configuration object containing the complete set of active screen regions.
 *
 * Screen regions define areas of the screen that have special meaning for Lens rendering,
 * such as safe rendering areas, UI button locations, keyboard areas, etc. This allows lenses
 * to adapt their content placement based on the host application's UI layout.
 *
 * This value is applied as a full replacement set: regions not included in the object are
 * removed. Pass `undefined` or omit this option to clear all screen regions.
 */
screenRegions?: ScreenRegions;

[andriiboliboksc]

@msilivonik-sc added should clear screen regions when they change from set to undefined (renders with regions, rerenders with undefined, asserts setScreenRegions({})). Also updated the screenRegions doc comment in both files as suggested.

[msilivonik-sc]

LGTM! Thanks!