IOC macro hard-coded to be component.P.lower() but breaks `More` buttons on `motor_embed.bob` screens

[OCopping]

If there are motors with different prefixes to the IOC name, when generating the motor screens, the IOC macro for the More buttons is incorrectly substituted with the prefix, not the service name.

E.g. for I19's new serial stages, they are on the service for STEP-14, with the prefix BL19I-MO-SRL-01. This means the IOC macro becomes https://i19-opis.diamond.ac.uk/bl19i-mo-srl-01 when it should be https://i19-opis.diamond.ac.uk/bl19i-mo-step-14.