insights: Add support to sort all series
Created by: CristinaBirkel
Closes https://github.com/sourcegraph/sourcegraph/issues/35711 Builds on https://github.com/sourcegraph/sourcegraph/pull/35873
Description
This moves the sorting step such that all series can be sorted. We've decided that for now it's okay if non-capture group series get sorted by default, given that it just affects the order of the keys.
A note on the tests: I couldn't figure out if it's possible to use some kind of mock resolvers here to mimic what the unit tests were doing before, but if you have any ideas here let me know!
Test plan
Via the UI I verified that capture group insights can still be sorted as expected. And by directly calling the API I verified that we can now also sort a non-capture group series.
