fix a test that is now async

Author: djeebus

packages/shared/pkg/storage/providers/storage_cache_test.go

@@ -227,6 +227,8 @@ func TestCachedFileObjectProvider_ReadAt(t *testing.T) {
 		require.NoError(t, err)
 		assert.Equal(t, len(fakeData), read)
 
+		time.Sleep(time.Millisecond * 20)
+
 		buf := make([]byte, 3)
 		read2, err := c.ReadAt(t.Context(), buf, 0)
 		require.NoError(t, err)