2.0.8: Fix AdminConfig::getAllConfigOfStore() caching the wrong store's config

The static memoization ignored $storeId - once populated by a query for
any one store, every later call within the same request returned that
same cached array regardless of which store was actually requested.

This surfaced as the admin layout's "<ADMIN_TITLE> | <page title>" browser
tab title silently losing its prefix on screens whose Livewire component
reads GP247_STORE_ID_GLOBAL-scoped config in mount() before the shared
layout resolves ADMIN_TITLE for the root store (e.g. LoginSocial's
AdminLivewire, ConfigForm subclasses using the default global storeId) -
the earlier global-store lookup poisoned the cache, so the later
root-store lookup for ADMIN_TITLE silently returned empty. Keyed the
cache by $storeId so each store is memoized independently.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>