IBEX GUI: 'Apply Changes' button indicates changes have been made when switching instruments

## Where?
/ibex_gui

The issue appears to be caused by the cached values of one insturment being compared to those of the insturment it was switched to, resulting in a perceived change.

## Reproducible?
Yes

### To Reproduce
If you switch from the local instument to an instrument where changes have been added to any of the DAE panels, and then switch back to your local instrument, the 'Apply Changes' button will appear to be yellow which indicated that a change as been made within the DAE Panels, although no change has occured.


## Acceptance criteria
- [ ] Switching between instruments does no result in 'Apply Changes' appearing yellow
- [ ] Changes made to local instrument's DAE panel will result in the 'Apply Changes' button appearing yellow