Add test criterion to confirm decorators correct in beamline device definition script

[CoePaul]

Background
In a typical beamline definition script, a sequence of devices are defined and a device factory decorator is applied to each.

Issue
The issue is that if a decorator is left out from a single device, there is currently nothing to detect this
( except for the Mark 1 human eyeball ).

Task
Make some form of automated test that will detect any discrepancies.

Caveat
This should not require a separate source of ground truth to provide a set of expected devices.
That would merely create the potential for two sources of error and the classic "Which one do You believe?" problem.

One option for a simple solution might be to insist that every python def line in such definition files comes with a decorator.

Acceptance Criteria

• That a beamline script with decorators proper and correct passes any new test
• That a beamline script with the decorator forgotten ( or deliberately removed in a local repo just to exercise the test )
  should cause the same test to fail

[jacob720]

Are there valid reasons to have a non-decorated function in a beamline module?

[oliwenmandiamond]

Isn't this is what dodal connect / describe is for?

You can list out all devices and see if any are missing / failing and ideally is run before merges that effect beamline file / device changes.

[jacob720]

i23.py breaks the test I've written as they have a function _is_i23_machine() that isn't a device or fixture. Either we need to change this module or decide it's ok to have functions that aren't devices or fixtures in beamline modules.
https://github.com/DiamondLightSource/dodal/actions/runs/23352187249/job/67933578388?pr=1984