Cannot expand/collapse panel immediately on mount

[bvaughn]

Context: https://github.com/bvaughn/react-resizable-panels/issues/206#issuecomment-1809369778

Repro: https://codesandbox.io/s/gracious-cannon-h5stq4

[timdown]

resize() also throws an error (probably unsurprisingly).

[bvaughn]

The overall problem is this:

• On mount, panels register with their parent group.
• The group schedules state updates with the newly registers panels (to re-render them with their appropriate sizes, based on their props/constraints).
• Your code is calling collapse (or expand, or resize) in between these two events– when the panel group isn't yet tracking the panels. (They're still in a pending-update state.)

Maybe I could change the registerPanel handler to update the committedValuesRef synchronously (to store the new panels) but I suspect other things might break if that's the only change. I'll look into this further soon though.

[bvaughn]

Fix published in @0.0.59

[bvaughn]

I don't love my fix. Filed #217 to follow up with a better approach.

[bvaughn]

0.0.60 fixes this in a better way.