Implement VisibilityThresholdModifier #972

Job	Run time
Automated Code Review	8m 33s
Test UIKit (Debug)	14m 19s
Build Test App and Frameworks	15m 58s
Launch Allure TestOps	1m 1s
Build Demo Apps	17m 21s
Test LLC (Debug)	19m 12s
Test SwiftUI (Debug)	27m 44s
Test E2E UI (Debug) (0)	36m 5s
Test E2E UI (Debug) (1)	27m 20s
	2h 47m 33s

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