[v4] [table] fix layout measuring headers on initial mount

[adidahiya]

The table component rendering process has a particular order of operations which relies on DOM interactions and React lifecycle methods happening in a certain way for all its measurement calculations to be accurate. Before this PR, TableQuadrantStack was taking measurements of column/row headers before they had a chance to render their contents, and using those width/height values to set the size of the quadrants for the initial render. This turned out to be buggy and produced visual gaps in the table when there were custom column/row header renderers, or in the case of frozen cols/rows.

The code in this PR adds some logic to Table2 and TableQuadrantStack to keep track of when the ColumnHeader and RowHeader components are fully mounted, after which we trigger a resync of the quadrant views with updated width/height measurements of the header areas. This fixes a few bugs.

Bug 1

Initial display of frozen cols/rows was wrong on initial render (before):

After:

Bug 2

Initial display of column headers with heights exceeding the minimum/default column header height was wrong on initial render(before):

After:

[blueprint-bot]

fix tests

Previews: documentation | landing | table | modern colors demo

[blueprint-bot]

fix formatting

Previews: documentation | landing | table | modern colors demo