[dagit] Fix wrapping in sidebar, disable reflow of fan-out
Summary: I updated the sidebar to wrap the pipeline, solid and IO names because things were basically useless. Thanks to "zero width space" characters, we can wrap on the underscores in the solid names which keeps things easy to read.
Test Plan: Updated snapshots
Reviewers: schrockn, alangenfeld
Reviewed By: schrockn
Differential Revision: https://dagster.phacility.com/D1549