Support extra EXT-OATCLS-SCTE35 tags during CUE-OUT

[bbayles]

This PR updates handling for the EXT-OATCLS-SCTE35. These are used in the "Elemental" style playlists that are supported by this library.

One subtlety that the library currently doesn't capture is that a segment can signal things like "program end" during a "cue out" interval. Below is a playlist from an Elemental service that shows this in action - the initial OATCLS message is repeated until a new explicit one is inserted.

I've updated the test case to capture this behavior.

#EXTM3U
#EXT-X-VERSION:3
#EXT-X-TARGETDURATION:8
#EXT-X-MEDIA-SEQUENCE:625441
#EXT-X-PROGRAM-DATE-TIME:2025-06-05T16:02:34.711Z

#EXTINF:6.13947,
playlist_4300k_20250605T160236_625441.ts

#EXT-OATCLS-SCTE35:/DAlAAAAAAAAAP/wFAVhB/69f+/+DtpcAP4ApPWwAAEBAQAA5C+fWA==
#EXT-X-CUE-OUT:120.120
#EXTINF:5.87253,
playlist_4300k_20250605T160242_625442.ts

#EXT-X-CUE-OUT-CONT:ElapsedTime=5.873,Duration=120.120,SCTE35=/DAlAAAAAAAAAP/wFAVhB/69f+/+DtpcAP4ApPWwAAEBAQAA5C+fWA==
#EXTINF:6.00600,
playlist_4300k_20250605T160248_625443.ts

# ...

#EXT-X-CUE-OUT-CONT:ElapsedTime=120.087,Duration=120.120,SCTE35=/DAlAAAAAAAAAP/wFAVhB/69f+/+DtpcAP4ApPWwAAEBAQAA5C+fWA==
#EXT-OATCLS-SCTE35:/DA2AAAAAAAAAP/wBQb+D39F9QAgAh5DVUVJ05v41X+/DA9XVVJMRDAwMDAwMzU4NjkQAAA8dWxB
#EXTINF:0.03337,
playlist_4300k_20250605T160442_625462.ts

#EXT-X-CUE-IN
#EXTINF:5.87253,
playlist_4300k_20250605T160442_625463.ts

#EXTINF:6.00600,
playlist_4300k_20250605T160448_625464.ts

[bbayles]

Checking in on this - I'm seeing playlists that need this modified behavior in the wild, hence my change request here. Thanks!

[bbayles]

Withdrawing - I found more cases to support.