bug: bug: push_out moves the pipette plunger higher instead of lower

### Overview

Exactly same bug as describe here: https://github.com/Opentrons/opentrons/issues/16991

#16991

Very annoying ... Seems just be a symbol issue in the code. 


### Steps to reproduce

_No response_

### Current behavior

_No response_

### Expected behavior

_No response_

### Operating system

None

### System and robot setup or anything else?

_No response_