The only way to know for sure if officer is there, is to ask prosecutor when you meet with them before court starts, although they have no obligation to tell you.
I have seen some prosecutors that are very honest about it and will tell you up front that the officer is not there, but there are other prosecutors that will not tell you anything and even if they know the officer will not show up they will still try and get you to plead guilty anyways.
If they won't tell you, the only way to really know for sure, is to tell them that you are ready to proceed to trial. Once court starts and they call your name, you will go up and they will ask your name. At this point, if the officer is not there then the prosecutor will say they are not ready to proceed, and will be either (1) withdrawing the charge, or (2) asking for another trial date. If the prosecutor is ready to proceed (meaning officer is there), they will say so, and then they will do the arraignment (read the charge and ask how you plead). You can at this time simply say "I have changed my mind and decided to plead guilty".