test(producer): rebake the variables-prod golden without the audio delay

Same cause as the missing-host-comp-id rebake, caught by shard-8 once the
earlier shard stopped failing and the rest of the matrix could run: this
reference also carries the encoder-priming delay this branch removes.

Reproduced in the CI container to the digit (correlation 0.42704173048439215,
lagWindows -12), rebaked there, and it now passes at correlation 1.0.

Worth recording: the shift here is 2048 samples (42.67 ms) at correlation
0.99983, exactly twice the 1024 of the other fixture. The delay compounds once
per un-compensated AAC generation, and this fixture's audio needs its duration
normalized, so it takes the pad/trim branch's re-encode and picks up a second
frame of priming on top of the mixer's. So the pre-fix error was not a fixed
21 ms - it grew with the number of times the audio was re-encoded.

All nine shards ran in that CI round with only this one failing, so the matrix
has now covered every fixture against this change.

Author: miguel-heygen

packages/producer/tests/variables-prod/output/output.mp4

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