DEFAULT_AD_BREAK_CUT_SAFETY_MARGIN_SEC

Default ad-break-cut safety margin, in seconds. A break is always hard-cut back to content at effectiveDuration + this margin at the latest, no matter how long the inserted ad media runs — the SDK never depends on the ad stream reaching its own end before returning to content. The small margin is grace so an ad whose length is close to the break duration can finish cleanly instead of having its final second(s) chopped at the exact boundary. Mirrors the web DEFAULT_AD_BREAK_CUT_SAFETY_MARGIN_SEC.