[v3-1-test] Exclude .pnpm-store from autoapi doc generation (#63386) (#63399)

The FAB provider has a .pnpm-store directory inside www/ that autoapi
was accidentally indexing, producing bogus API docs pages.
(cherry picked from commit 2daf4b9290f4e65f6c01de4f2a1f8d2120f25256)

Co-authored-by: Jarek Potiuk <jarek@potiuk.com>
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>