ci: reduce office-hours reminder spam by posting only on most recent PR per user#1150

exploreriii merged 1 commit intohiero-ledger:mainhiero-ledger/hiero-sdk-python:mainfrom

TianyangRen:fix/office-hours-spam-cleanTianyangRen/hiero-sdk-python:fix/office-hours-spam-cleanCopy head branch name to clipboard