test(web): remove redundant useGridLayout test

The useGridLayout hook is a thin wrapper around useCalendarGridLayout
that passes DAYS_IN_VIEW=7 and isWeekInteractionMotionActive. All
functionality is already covered by useCalendarGridLayout.test.tsx
which tests the same 7-day layout measurements.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: tyler-dane