Bug: When setting up alerts for insights with All Events as the only series, "A - Null" is the only option shown to be tracked.

[benHPostHog]

Bug Description

Bug description

When setting up alerts for insights with All Events as the only series, "A - Null" is the only option shown to be tracked. I am yet to confirm whether this is only visual and whether the alert still works correctly but will update when my next alert comes in (or if it doesn't!).

If you are on PostHog Cloud it would be really valuable if you can share any links where the problem occurs. This speeds up our ability to troubleshoot tremendously.
https://us.posthog.com/project/93136/insights?tab=alerts - from original ticket reporter
https://us.posthog.com/project/98852/insights/cGpSonhv/alerts - from my (Haynes) test org

How to reproduce

1. If necessary, create an Insight for all events / or view an existing Insight that looks at all events
2. Create an alert
3. See the only option available as "A - Null"

Additional context

Debug info

Kind: bug
Target area: data_management
Report event: http://go/ticketByUUID/ead2c4f4-c9e4-4695-9e23-0397c4ffad3e
Session: https://us.posthog.com/project/sTMFPsFhdP1Ssg/replay/0193f39c-d4e7-79e3-9c27-e3bc11067c25?t=852
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%220193f39c-d4e7-79e3-9c27-e3bc11067c25%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/93136/insights?tab=alerts
Sentry: http://go/sentryUS/93136
Persons-on-events mode for project: person_id_override_properties_on_events