Bug: Replay mp4 exporter cut-off

Bug Description

Bug description

The replay mp4 exporter seems to be cutting the last minute or so off in the exported video.

How to reproduce

1. export mp4 of replay
2. view replay
3. skip to end

Additional context

From: https://posthoghelp.zendesk.com/agent/tickets/54036 (moved to PostHog: https://us.posthog.com/project/2/support/tickets/55128)

Debug info

Kind: support

Target area: session_replay

Report event: http://go/ticketByUUID/8892f671-d5a0-4c78-8304-5551b603f822

Session: https://us.posthog.com/project/sTMFPsFhdP1Ssg/replay/019d1ae7-4e74-7fcc-86b6-5711d61dc627?t=346

Exceptions: https://us.posthog.com/project/2/error_tracking?filterGroup=%7B%22type%22%3A%22AND%22%2C%22values%22%3A%5B%7B%22type%22%3A%22AND%22%2C%22values%22%3A%5B%7B%22key%22%3A%22%24session_id%22%2C%22value%22%3A%5B%22019d1ae7-4e74-7fcc-86b6-5711d61dc627%22%5D%2C%22operator%22%3A%22exact%22%2C%22type%22%3A%22event%22%7D%5D%7D%5D%7D

Location: https://us.posthog.com/project/235287/replay/019d0cdb-11ec-788d-a35c-a4adae2df61f

Persons-on-events mode for project: person_id_override_properties_on_events

Begin in the session_replay area and trace the MP4 export path using the supplied reproduction: export a replay, open it, and skip to the end. Compare the replay duration with the exported file and use the linked support session and ticket as the failing example; done means the exported MP4 includes the final minute.