Use derived signals for image plane #1021
Description
There are a number of places in mx-bluesky where we derive a move in the image plane from the gonio co-ordinates (e.g. https://github.com/DiamondLightSource/mx-bluesky/pull/950/files#diff-8285cd27855e0de278dc815e22a1d4536a8a64ffb880860d3a604e1a3e0d23dbR70-R73). Following DiamondLightSource/dodal#1164 there will be derived signals for this in the ophyd device. We should take all the places we do this maths in mx-bluesky and instead use the derived signals.
Acceptance Criteria
- Derived signals are used for oav plane calculations