formatElapsedTime proposal for <10s

Summary:
This diff proposes that we show msec-level granularity in formatElapsedTime if the value is less than 10 seconds. Why? Currently:

• If the value is less than 1 second, we show milliseconds, e.g. 425ms. This seems fine.
• Otherwise, we show hh:mm:ss. This is not great when we're only looking 1-10 seconds, e.g. 00:00:02. Millisecond-level granularity is likely to be useful here.

In this change:

• If the elapsed time is less than ten seconds, render a seconds-level value with milliseconds, e.g. 0.425s, 4.887s, etc.
• Otherwise, continue using the hh:mm:ss format: 00:00:32, 00:02:38, etc.

Test Plan: View Runs table, verify changes described above.

Reviewers: bengotow, dgibson, prha, johann

Reviewed By: bengotow

Differential Revision: https://dagster.phacility.com/D5868