Fix #1296: configurable video interstitial auto-close

[mdanylov-sigma]

Summary

Adds a publisher-configurable isAutoCloseOnCompletionEnabled flag (default true, preserving existing behavior) on VideoControlsConfiguration, exposed on InterstitialRenderingAdUnit, RewardedAdUnit, and MediationBaseInterstitialAdUnit. When disabled, a full-screen video interstitial without a companion/end card no longer auto-dismisses when playback completes — the publisher (or the rewarded close-action flow) controls when it closes.

Closes #1296

Behavior

• Default (true): unchanged from current behavior — video without a companion still auto-closes on completion.
• false: [modalManager creativeDisplayCompleted:] is still called unconditionally (so rewarded completion is still reported to ModalManager and rewarded close-action handling — closeButton/autoClose/unknown — still runs correctly), but the automatic dismissInterstitialModalState() call is skipped.
• Non-rewarded interstitials without a companion still get a close ("X") button via the existing closeDelay countdown in ModalViewController, independent of this flag, so they can never get stuck.

Testing

• PrebidMobileTests (unit): 25/25 passed, including new tests:
  • testInterstitialWithoutCompanionAutoClosesByDefault
  • testInterstitialWithoutCompanionCanDisableAutoClose
  • testRewardedCompletionIsReportedWhenAutoCloseIsDisabled — explicitly verifies ModalManager.creativeDisplayCompleted(_:) still fires for a rewarded ad when auto-close is disabled.
  • testAutoCloseOnCompletion (config default/override)
• PrebidDemoSwiftUITests (real UI test, live ad serving): testInAppVideoInterstitialAd passed.

API / compatibility

• Additive @objcMembers property, consistent with the existing isSoundButtonVisible pattern across all three ad unit surfaces — no Objective-C interop concerns, no breaking changes, default preserves current behavior for existing integrations.

[OlenaPostindustria]

When isAutoCloseOnCompletionEnabled is set to false, the video just ends without providing an option to replay. Since video banners have a Watch Again button in this scenario, would it make sense to make the behaviour consistent? Alternatively, we could have the video automatically loop until the ad is closed.

[OlenaPostindustria]

LGTM, left a suggestion

[OlenaPostindustria]

It would also be good to document the new property in the public documentation

[OlenaPostindustria]

LGTM!

[YuriyVelichkoPI]

Please support new property in ORTBAdConfiguration and update the spec for Ad Experience Controls respectively

https://docs.prebid.org/prebid-mobile/modules/rendering/combined-ad-experience-controls.html

[mdanylov-sigma]

Addressed in 097c52d: the value now parses through ORTBAdConfiguration, rewarded ads defer to rwdd.close.action, and the public documentation update is in prebid/prebid.github.io#6697.

[YuriyVelichkoPI]

LGTM