ENH: Improvements to start/stop behaviour of Eyetracker Record Components

[TEParsons]

Attempt to fix the problem identified in #6456

The problem:

• An EyetrackerRecordComponent set to "Stop only" doesn't have a start time, so was never marked with .status = STARTED
• Marking it with .status = STARTED calls a property/setter pair which actually starts the eyetracker, this is generally inadvisable as sometimes we want to just tell Builder it's started (i.e. when there's a new Component but not a new device, we want to mark the Component as STARTED but don't want to start the device again)
• This meant the eyetracker was never stopped so crashed when the experiment finished

The solution(s):

• Instead of .status = STARTED starting the eyetracker, have the start code in a function called startRecording and call this function explicitly in the Builder code (ditto for stopping the recording)
• Remove the property/setter so that status returns to being just an attribute for tracking progress in Builder
• If the component is "Stop only", have the Component set .status = STARTED at the very beginning (which we can now do safely)

Bonus:

• I noticed that the dollar signs by the start/stop aren't being hidden/shown according to state, so I fixed that while I was in the neighbourhood

[RebeccaHirst]

We have tested this and unfortunately it throws the error message

Traceback (most recent call last):
File "C:\Users\lpykgw\Downloads\hello (1)_lastrun.py", line 935, in
run(
File "C:\Users\lpykgw\Downloads\hello (1)_lastrun.py", line 807, in run
if tThisFlipGlobal > etRecord_3.tStartRefresh + 1.0-frameTolerance:
TypeError: unsupported operand type(s) for +: 'NoneType' and 'float'
################ Experiment ended with exit code 1 [pid:12848] #################

this is because tStartRefresh is never created in the compiled python code

if etRecord_3.status == NOT_STARTED:
            etRecord_3.status = STARTED
        # if etRecord_3 is stopping this frame...
        if etRecord_3.status == STARTED:
            # is it time to stop? (based on global clock, using actual start)
            if tThisFlipGlobal > etRecord_3.tStartRefresh + 1.0-frameTolerance:
                # keep track of stop time/frame for later
                etRecord_3.tStop = t  # not accounting for scr refresh
                etRecord_3.tStopRefresh = tThisFlipGlobal  # on global time
                etRecord_3.frameNStop = frameN  # exact frame index
                # add timestamp to datafile
                thisExp.addData('etRecord_3.stopped', t)
                # update status
                etRecord_3.status = FINISHED
                etRecord_3.stopRecording()

[TEParsons]

Give it a go now with the new commits :)