filtering date/timestamp properties only accepts unix timestamps

[idoqo]

Filtering by date/time properties in the funnel/event filter UI only accepts Unix millisecond timestamps. There is no indication of this in the UI, and entering natural date formats causes the chart to fail with an "error showing chart" message.

Steps to reproduce

• Open a funnel or event chart
• Add a filter on a date/time property (in my case it was created_at)
• Select an operator (e.g. Greater than or equal to)
• Enter a date value in a natural format such as 2024-01-01 or 2024-01-01T00:00:00Z
• Observe the chart area