Make property graph object descriptions better translatable

Make property graph object descriptions better translatable

getObjectDescription() currently constructs property graph-related
object descriptions incrementally with appendStringInfo().  This
effectively fixes the word order in English, which makes the messages
difficult to translate naturally into languages such as Japanese.

Author: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Reviewed-by: Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/20260528.121622.1662808269492494574.horikyota.ntt%40gmail.com