esc_status in px4 would contain individual current for each ESC and since this is not possible to measure on the mini ESC, the esc_status message does not contain any current measurements. So the total current goes into the Battery Status message.
Please make sure you enable publishing of battery status in the voxl-esc driver here :
param_get(param_find("VOXL_ESC_PUB_BST"), ¶ms->publish_battery_status);and the status is published here