[dagit] Make logs scrolling table handles narrower
From an internal report.
Repair a couple of issues related to the logs scrolling table:
- Left-most text selection often runs into the draggable column divider, which breaks the selection out of the desired cell.
- Event type tags end up overflowing into the neighbor cell when the column is narrow enough.
Fix these by doing a bit of CSS refactoring to simplify rendering. Hopefully this doesn't overlook anything obvious.
Test Plan: View a run in Dagit. Verify proper rendering of all rows. Resize columns, verify that content is not overlapping weirdly. Select text in cell, verify that I can do so.
Reviewers: bengotow, prha
Reviewed By: prha
Differential Revision: https://dagster.phacility.com/D7643