fix(web): remove duplicate useI18n in ProjectView reattach-restore mock (#2743)

PR #2724 (commit dbc8677) added a useI18n mock to fix the runtime
`No "useI18n" export defined` error in ProjectView.reattach-restore.test.tsx,
but ended up with TWO useI18n keys in the same object literal — the
intended new entry at the top of the mock, plus an apparently-existing
second entry at the bottom. main is now red at typecheck:

  apps/web typecheck: tests/components/ProjectView.reattach-restore.test.tsx(41,3):
    error TS1117: An object literal cannot have multiple properties with
    the same name.

Drop the duplicate (the second, less-complete entry), keeping the
first one that matches the pattern used by the 9 sibling ProjectView
test files (useI18n returning { locale, setLocale, t }).

Verification: pnpm --filter @open-design/web typecheck → exit 0,
pnpm --filter @open-design/web test ProjectView.reattach-restore →
10/10 pass.

Author: whoughton