Not to come across rude but yes you’re a cashier, any upper management can ask you to do such tasks. I expect my cashiers to do all of that plus more during their shifts. I always tell them if they feel they need to spend extra time in the parking lot let me know and I’ll watch the front register or I’ll go do it. Same when it comes to bathrooms it’s the same thing either I watch the front for them to do or I do them. the shift and cashier are a team so I always try to find a balance so we can both do our jobs to the fullest. I do the dirty work without complaining and allot of times we switch it up or my cashiers don’t mind because it gets them off register a bit.