fix(auth): preserve default lock acquire timeout

[pjpjq]

Description

Fixes #2492.

SupabaseClient was always forwarding lockAcquireTimeout to SupabaseAuthClient, even when the caller did not configure it. Because the forwarded property was explicitly undefined, auth-js' default merge treated it as an override and replaced the documented 5000 ms default with undefined.

This PR only includes lockAcquireTimeout in the auth client options when it is actually defined, so default-config clients keep auth-js' fallback while explicit values still pass through.

Testing

• pnpm install --frozen-lockfile
• pnpm nx test:unit supabase-js --testPathPatterns=SupabaseAuthClient.test.ts
• pnpm prettier --check packages/core/supabase-js/src/SupabaseClient.ts packages/core/supabase-js/test/unit/SupabaseAuthClient.test.ts
• pnpm exec eslint packages/core/supabase-js/src/SupabaseClient.ts packages/core/supabase-js/test/unit/SupabaseAuthClient.test.ts (0 errors; existing warnings only)
• git diff --check

Notes:

• pnpm nx typecheck supabase-js was blocked before running by an existing workspace sync warning from Nx.
• pnpm nx lint supabase-js was blocked by a missing optional Expo integration lint dependency (eslint-config-expo/flat), so I ran ESLint on the changed files directly instead.

[mandarini]

Thanks @pjpjq, the fix here is correct, but #2392 (shipped in 2.107.0) removed navigator.locks as the default coordination mechanism, so the infinite-wait this was guarding against no longer applies to default-config clients. Closing in favour of that broader fix.