Test fluo optimisation

[DominicOram]

Successfully tested on i03 today, found the following issues:

• Set transmission works
• Optimise doesn't actually use the zebra, manually opens/closes shutter
• Therefore added sample shutter in for i03 and used this instead of zebra (TODO: remove zebra from optimise)
• Acquire/Erase states needed to be set as numbers, not strings
• The comment about no callback until collection finished is wrong instead, logic is:

arm_status = await_value_in_list(self.detector_state, self.detector_busy_states)
self.erase.put(EraseState.ERASE.value)
arm_status &= self.acquire.set(AcquireState.ACQUIRE.value)
arm_status.wait(1) # Detector now taking data
return await_value(self.acquire_rbv, 0) # This will return don when the collection is finished 

• Deadtime logic - need to wait for it to go above the threshold before flipping direction then returning when below
• Implement high limit (default 0.1) (for both algorithms)
• Finally, we got some reasonable results but they're not exactly the same as GDA. Further work is needed (outside this issue)to finish off.

Acceptance Criteria

• The above is tidied up into a PR and merged (with tests)