feat: Cherry-pick DH-18779: Auto-resize column header groups#2563

vbabich wants to merge 1 commit intodeephaven:release/v0.85deephaven/web-client-ui:release/v0.85from

vbabich:dh-18779-auto-resize-groupsvbabich/web-client-ui:dh-18779-auto-resize-groupsCopy head branch name to clipboard