Using layer z to calculate total layer number is not
precision, because for some models with sharp top
layer, the top layer may be empty.
Check the final layer change in final gcode file.
This must be same with total layer number.
Jira: Studio-2123
Signed-off-by: salt.wei <salt.wei@bambulab.com>
Change-Id: I5d001a8bb9548c3fb5f67fda966051ac3bb16502