test(deckgl): update Polygon/Scatter tests for consolidated index

After the layer consolidation, Polygon and Scatter export buildQuery
and transformProps as named exports from their index.tsx instead of
from separate files. Update the tests' imports accordingly. Also
export transformProps (was a private function) since the tests rely
on calling it directly.

Drop Multi/controlPanel.test.ts: its assertions tested the structure
of the standalone controlPanel object which no longer exists; the
build itself validates the controls.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>