Feature Request: Improve recording matching in Funnels for mixed web+backend events

Feature request

Is your feature request related to a problem?

When a funnel mixes backend+frontend events, recordings will only show in steps that look at frontend events where the session replay is enabled, but no recordings will show when looking at backend events in the same funnel.

Describe the solution you'd like

This is confusing, so we either need to use a time-based matching for recordings or display a message that backend events won't show any recordings.

Describe alternatives you've considered

• Include at least one frontend event and watch the recordings based on that, but I can't filter when the user dropped as easily
• Move my events to the frontend

Additional context

From: https://posthoghelp.zendesk.com/agent/tickets/34080 (moved to PostHog: https://us.posthog.com/project/2/support/tickets/36112)

Debug info

Kind: support

Target area: session_replay

Report event: http://go/ticketByUUID/3d03383a-8c97-46c0-9a39-2814b9d5a795

Session: https://us.posthog.com/project/sTMFPsFhdP1Ssg/replay/0197f8d2-f4e1-7402-842e-fdca2a203c2f?t=2284

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%220197f8d2-f4e1-7402-842e-fdca2a203c2f%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/103241/person/0197f41e-a14d-77e3-a944-fc716c063815#activeTab=sessionRecordings&

Persons-on-events mode for project: person_id_override_properties_on_events

No source files or tests are named. Start by reproducing a funnel that mixes backend and frontend events, with session replay enabled for the frontend event, and compare recording results for each step. Done means backend-event steps either match recordings by time or clearly explain that recordings are unavailable.