[HLS] Support FairPlay-signaled CMAF with ClearKey

[ldzhjn]

Description

Preserve a 128-bit hexadecimal KID from a FairPlay skd:// URI and expose the
track encryption KID as Common Encryption information when an encrypted CMAF
initialization segment contains no usable PSSH box.

This allows a user-configured ClearKey decrypter to open SAMPLE-AES fMP4
streams that use FairPlay HLS signaling. It does not implement FairPlay key
management or license acquisition.

Motivation and context

Some CMAF HLS streams signal KEYFORMAT="com.apple.streamingkeydelivery" and
use cbcs, while carrying the default KID only in the skd:// URI and/or the
track's tenc box. Without a PSSH box, the initialization segment previously
returned no DRM information, so the ClearKey session could not be matched to
the configured KID.

The parser now accepts only skd:// values that normalize to exactly 16 bytes
of hexadecimal data. Other FairPlay asset identifiers remain unchanged.

How has this been tested?

• All 62 native unit tests pass on macOS.
• Added an HLS regression test for a hyphenated, uppercase skd:// KID and
  SAMPLE-AES/CBC mode.
• Built successfully for tvOS arm64 against Kodi 22 Addon API 2.0.3.
• Verified playback of a 3840x2160 50 fps HEVC 10-bit CBCS CMAF HLS stream on
  Apple TV using a configured ClearKey, including video and audio decryption.

Screenshots (if appropriate):

Not applicable.

Types of change

• Bug fix (non-breaking change which fixes an issue)
• Clean up (non-breaking change which removes non-working, unmaintained functionality)
• Improvement (non-breaking change which improves existing functionality)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that will cause existing functionality to change)
• Cosmetic change (non-breaking change that doesn't touch code)
• None of the above (please explain below)

Checklist:

• I have read the Contributing document
• My code follows the Code Guidelines of this project
• My change requires a change to the Wiki documentation
• I have updated the documentation accordingly

[CastagnaIT]

not bad idea but needs a bit of more cleanups

[ldzhjn]

@CastagnaIT PTAL

[CastagnaIT]

I made some tests i think its ok
thank you