Deprecate LazyGridPrefetchStrategy in Compose Foundation

Deprecated LazyGridPrefetchStrategy and related prefetch APIs (LazyGridPrefetchScope, LazyGridPrefetchResultScope) in favor of LazyLayoutCacheWindow for lazy grid prefetching customization.

Test: n/a only api changes
Relnote: "Deprecated `LazyGridPrefetchStrategy`, `LazyGridPrefetchScope`, and `LazyGridPrefetchResultScope`. Prefetching behavior should be configured using `LazyLayoutCacheWindow` on `LazyVerticalGrid` or `LazyHorizontalGrid`. `LazyLayoutCacheWindow` provides a declarative, viewport-based caching mechanism that automatically prepares items ahead of and keeps items behind the visible window without requiring complex imperative scheduling callbacks. The new API is simpler and requires less configuration steps than `LazyGridPrefetchStrategy`."
Change-Id: Ic3a014a971d6c83994af0dad49a1493c9bc44f50