[dagit] Add a polling query for Run logs
Branch LogsProvider to use a polling query in cases where the websocket is not open. The query uses after to retrieve slices of logs.
Depends on https://dagster.phacility.com/D8220.
Test Plan: Force query branch in code. Launch a run. Verify that polling occurs correctly, and that the Gantt and logs table update correctly as well. Verify that the polling terminates properly when the status reaches a completed state.
Reviewers: alangenfeld, dgibson, bengotow
Reviewed By: bengotow
Differential Revision: https://dagster.phacility.com/D8224