Fix race in blockstore test suite

Signed-off-by: Jakub Sztandera <kubuxu@protocol.ai>

lib/blockstore/badger/blockstore_test_suite.go

@@ -183,6 +183,8 @@ func (s *Suite) TestAllKeysRespectsContext(t *testing.T) {
 	require.True(t, ok)
 
 	cancel()
+	// pull one value out to avoid race
+	_, _ = <-ch
 
 	v, ok = <-ch
 	require.Equal(t, cid.Undef, v)