Feature Request: Make breakdown display tooltip render within viewport on large lists (or scroll)

Feature request

Is your feature request related to a problem?

When an insight has many breakdowns, the tooltip that shows them may bleed outside the viewport with no option to scroll.

This makes it difficult to analyze big cohorts.

Describe the solution you'd like

• Make the tooltip render responsively within the viewport
• Consider adding it as a separate area within the chart, similar to how we render the "legend" as part of the chart component (shown below)

Describe alternatives you've considered

• Look at the table that's rendered when you open the insight if it's a UI insight, or convert to a table for SQL insights

Additional context

From: https://posthoghelp.zendesk.com/agent/tickets/35787 (moved to PostHog: https://us.posthog.com/project/2/support/tickets/37143)

Debug info

Kind: support

Target area: analytics

Report event: http://go/ticketByUUID/60556592-b1a6-41bc-8425-3ca2e7a8daf2

Session: https://us.posthog.com/project/sTMFPsFhdP1Ssg/replay/01988a2e-82f7-76e1-b3c4-37f014b039ea?t=4662

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%2201988a2e-82f7-76e1-b3c4-37f014b039ea%22%5D%2C%22operator%22%3A%22exact%22%2C%22type%22%3A%22event%22%7D%5D%7D%5D%7D

Location: https://eu.posthog.com/project/67025/dashboard/227985

Persons-on-events mode for project: person_id_override_properties_on_events

Start by locating the breakdown tooltip and the chart component that renders its legend. Reproduce the large-breakdown case described in the issue, then compare the tooltip and chart behavior against the viewport constraint. Done means the breakdown remains usable within the viewport, either by responsive placement or scrolling.