fix(youtube): read the sort token from the dropdown chip on channels using it

[Priveetee]

Refs InfinityLoop1308/PipePipe#2549

Commits

• Priveetee@88e1f0e

Summary

• Fix YouTube channel Videos tab sorting (latest / popular / oldest) being silently ignored on a subset of channels.
• YouTube now serves the sort chips as a single "Sort by" dropdown on those channels, with the real sort tokens hidden inside its sheet. The extractor was reading the chipBar by index and picked up "Members only" / "Public" filter tokens instead of sort tokens.
• Keep the existing flat chipBar layout working unchanged.

Problem

YouTube rolled out a second chipBar layout on the channel Videos tab. Two layouts now coexist:

flat (still common):   chips = [Latest, Popular, Oldest], each with a direct continuationCommand.token
dropdown (new):        chips = [SortBy (DROP_DOWN), MembersOnly, Public]
                       sort tokens live in SortBy.tapCommand.showSheetCommand.sheetViewModel.listViewModel.listItems[]

getSortContinuationToken did chips.getObject(sortIndex) with latest=0 / popular=1 / oldest=2. On the dropdown layout, index 1 is the "Members only" filter and index 2 is the "Public" filter, so popular loaded members-only videos and oldest loaded public-filter videos in the default order.

Observed on one of the reported channels (UCfMaMDIYLcZbN2aagsTUO5Q), first five video IDs per sort:

before:
latest   = gBBZSFojEno qevwjRTW7HQ 4xNd3jhMVUQ bMaHJf9M9BI ZRK4UjqN5w8
popular  = (0 items)
oldest   = gBBZSFojEno qevwjRTW7HQ 4xNd3jhMVUQ bMaHJf9M9BI ZRK4UjqN5w8

Changes

• YoutubeChannelTabExtractor#getSortContinuationToken: when the first chip is CHIP_VIEW_MODEL_DISPLAY_TYPE_DROP_DOWN, read the sort token from its sheet listItems[sortIndex] instead of chips[sortIndex].
• Add extractContinuationTokenFromListItem to pull continuationCommand.token out of commandExecutorCommand.commands[] (it sits next to an entityUpdateCommand, so no hardcoded command index).
• Flat-layout path untouched.

Validation

• ./gradlew :extractor:compileJava
• Local extractor probe against reported channels with the dropdown layout.

After, same channel:

latest   = gBBZSFojEno qevwjRTW7HQ 4xNd3jhMVUQ bMaHJf9M9BI ZRK4UjqN5w8
popular  = cQ7X8VEiCko QAan0CmkYEA 33v-L43JCeo gBBZSFojEno 0h6Ig83cjPw
oldest   = -b22efhXG7I SqmxRfFj318 X5v_yfcI0k0 xoQO7XroBko ZJ6xFPY3wJA

Also probed three more reported dropdown channels (UC9YOQFPfEUXbulKDtxeqqBA, UCpPQTM5BojSeZJC_Q-vvs5A, UCKAmgxBSTqfSGz6OPxhrCZA): all three sorts return distinct item orders after the fix.

No regression on a flat-layout channel (UCBJycsmduvYEL83R_U4JriQ): latest / popular / oldest stay distinct, same as before.

Notes

• Relies on the dropdown listItems order being [Latest, Popular, Oldest], which matched every channel I captured and matches YouTube's UI. If YouTube reorders it, the helper returns null and we throw a clean ParsingException instead of silently loading the wrong content.
• This only touches the Videos tab chipBar. #2546 (channel search "Could not get url") is a separate bug on the search path and is not addressed here.