Fix reversed sort and cap data series

Created by: unclejustin

Related to https://github.com/sourcegraph/sourcegraph/issues/34653 Depends on https://github.com/sourcegraph/sourcegraph/issues/36660 Closes https://github.com/sourcegraph/sourcegraph/issues/36589

• Fix date sorting
• Cap data series limit to the lesser of 20 or total series

Test plan

• Open any filterable insight
• Sorting date "Oldest" should show oldest series first
• Should not let you enter more than the lesser of 20 or total series for data series limit

App preview:

• Web
• Storybook

Check out the client app preview documentation to learn more.