MuSR: (Discussion) Improve mechanism for setting slew rate differently when triton is in use

As an instrument scientist I would like a robust way of setting the slew rate differently if I am using a triton. Currently the script in use on MuSR checks whether the config contains the word "triton". This has already failed once due to the config name being unreachable (https://github.com/ISISComputingGroup/IBEX/issues/6398). It could also be prone to mistakes as having behaviour change based on a config name is not expected behaviour generally in IBEX.

## Acceptance Criteria
* The exact requirements of the behaviour are found
* There is another mechanism for deciding what the slew rate should be e.g. checking if the triton IOC is running?