Remove default macro values from st.common's

Suggested - Timebox

As a developer, I would like to remove default macro values from `st.common` files so that we can benefit from a single source of truth in `config.xml` once #8445 is merged.

## Explanation
#8445 made it so macro default values are now loaded in by `icpconfig` from `config.xml` as such, setting defaults on macros when passing them into files, e.g. `$(MACRO=DEFAULT)` is unnesecary, and should be removed for all ioc macros that are defined by an ioc's `config.xml`

### Additional Information

- _This ticket should only deal with changes within [Epics IOC](https://github.com/ISISComputingGroup/EPICS-ioc)_
- _#8445 must be completed before work begins on this ticket._

# Acceptance Criteria
- [ ] Default values are removed from ioc macros in `st-common` if they are defined by `config.xml`.
- [ ] Default behaviour of altered ioc's is unchanged.
- [ ] A new ticket is opened to continue this work.