5.8.3 - iOS/tvOS build fix for the #2 VT probe

Fixed

iOS / tvOS build fix for the #2 decodability probe.

5.8.2 added a per-format VideoToolbox decodability probe (VTCapabilityProbe.canHardwareDecode) but used kVTVideoDecoderSpecification_RequireHardwareAcceleratedVideoDecoder without the iOS 17 / tvOS 17 availability guard (the symbol did not exist on iOS before 17). That compiled on macOS but failed the iOS / tvOS simulator build. It is now guarded the same way HardwareVideoDecoder is, with no behavior change on the shipping deployment targets.

The macOS build (AetherPlayer) was unaffected in 5.8.2; this release matters only for the tvOS / iOS consumer (Sodalite). The #2 functional fix is unchanged from 5.8.2.

Full Changelog: 5.8.2...5.8.3