Fixes for Strip ReadoutGeometry and Digitization
Fixing a few issues that were noticed when debugging the new ITkStrip Digitization.
- Fixing sign of angle in calculation of distance to nearest cell
- Using SiHitCollection.find(SiCellId) instead of SiHitCollection.find(Identifier) which avoids an extra conversion step and also works for both SCT and ITkStrip which the latter doesn't
- Reinstate SDO formation, which now works again after these fixes