insights: Filter out context from 1-click create insight flow

Created by: Joelkw

Search contexts don’t yet work in insights, backend or frontend (we know this). If you include a context: in your code insight, it flatlines the graph and every datapoint is “today’s value” because contexts break our historical revisions.

Until we support this, let's filter them out the "carried over" query when you hit the 1-click create insight button.