Revert "[dagit] Add refresh countdown to Runs page"
This reverts commit 70fe24ff0d5abe234e59f34b409010abd521b6a9.
For some reason, the refresh countdown on the Runs page is behaving badly when combined with the root query refetch triggered by hovering on status tags: it goes into a refetch loop.
Revert while I investigate.
Test Plan: Load Runs page, hover on a status tag. Verify that the page doesn't crash.
Reviewed By: schrockn
Differential Revision: https://dagster.phacility.com/D5503