insights: update granularity control

Created by: Joelkw

The granularity control isn't intuitive. If/when we have more datapoint nuance and control (more scalability) then we should update this!

In particular, users seem to think in terms of "how many years of history, and how often do I want the datapoint" like "3 years, monthly" rather than "12 dots, spread them out 3 months apart so it's 3 years total"