Issue with safe-z state management

[brendenpelkie]

Duet3D Firmware Version

No response

Steps to reproduce this bug

Steps:

1. Load a new deck instance in python
2. Load labware associated with that deck/machine
3. Re-run the deck cell

Now your safe-z height is the default safe z for the deck, but the labware is still defined and can be associated with tools and accessed by the machine. Since the safe-z is too low, you will have a collision. We ran into this issue when picking up a pipette tip.
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Snippet:

// Paste your code here :)