fix(shwap/store): avoid double cache check (celestiaorg#3788)

* `Store`  checks the combined cache already, so there is no need to recheck it in `CachedStore`
* `Store.HasByHeight` to use `cache.Has` to check accessor presence instead of `cache.Get`

This fixes a performance bug, rather than something that was broken.

store/store.go

@@ -356,9 +356,7 @@ func (s *Store) HasByHeight(ctx context.Context, height uint64) (bool, error) {
 }
 
 func (s *Store) hasByHeight(height uint64) (bool, error) {
-	acc, err := s.cache.Get(height)
-	if err == nil {
-		utils.CloseAndLog(log, "accessor", acc)
+	if s.cache.Has(height) {
 		return true, nil
 	}
 

store/store_cache.go

@@ -43,10 +43,7 @@ func (s *Store) WithCache(name string, size int) (*CachedStore, error) {
 
 // HasByHeight checks if accessor for the height is present.
 func (cs *CachedStore) HasByHeight(ctx context.Context, height uint64) (bool, error) {
-	if cs.combinedCache.Has(height) {
-		return true, nil
-	}
-
+	// store checks the combinedCache itself, so we can simply passthrough the call
 	return cs.store.HasByHeight(ctx, height)
 }