XYZ override rework

[w-e-w]

Description

changes

• use apply_override for Clip skip
• use override for uni_pc_order
• use override of sd_vae
• remove unused code

some axis is implemented using direct setting modification
but all these are not settings that are particularly special that happens in the early stages of the pipeline so override settings does work
so no reason to not switch to override is as it is more consistent as override has a higher priority
and has the benefit of simplified code as we don't need to re-implement the restoration of originating

higher priority as in for example clip, is is possible to forgot you have a override setting set in the UI that changes the clip
if you did not remove the setting then the override on the setting will have priority over the xyz axis

functionally nothing has changed aside from Automatic vae choices

Checklist:

• I have read contributing wiki page
• I have performed a self-review of my own code
• My code follows the style guidelines
• My code passes tests