Tidy up device creation for full grid scan

[DominicOram]

Fixes #660

To test:

1. Confirm tests pass

[codecov]

Codecov Report

Merging #661 (fbd1edc) into main (822aa06) will increase coverage by 0.71%.
The diff coverage is 100.00%.

❗ Current head fbd1edc differs from pull request most recent head 08ebea8. Consider uploading reports for the commit 08ebea8 to get more accurate results

@@            Coverage Diff             @@
##             main     #661      +/-   ##
==========================================
+ Coverage   89.04%   89.75%   +0.71%     
==========================================
  Files          34       34              
  Lines        1488     1494       +6     
==========================================
+ Hits         1325     1341      +16     
+ Misses        163      153      -10     

Impacted Files	Coverage Δ
...rc/artemis/experiment_plans/fast_grid_scan_plan.py	82.87% <100.00%> (+0.44%)	⬆️
src/artemis/experiment_plans/full_grid_scan.py	70.31% <100.00%> (+0.95%)	⬆️
...rtemis/experiment_plans/oav_grid_detection_plan.py	100.00% <100.00%> (+3.44%)	⬆️
src/artemis/parameters/beamline_parameters.py	100.00% <100.00%> (+14.63%)	⬆️
src/artemis/parameters/constants.py	100.00% <100.00%> (ø)

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[dperl-dls]

great, thanks for tidying this up! I just added a little sneaky change (making the get beamline params a bit more general, in prep for adding beamlines) and a couple more tests, so I'll approve this and leave for you to look at

[DominicOram]

I like moving to the dictionary for BEAMLINE_PARAMETER_PATHS but I would rather limit the places we pull out the environment variable. Can we reuse either get_beamline_name in dodal or get_beamline_name here? This will also mean we can better handle the simulation case.

[dperl-dls]

Done, now this depends on DiamondLightSource/dodal#66
This will require setting and S03 env var as currently implemented because I didn't want to put S03 as a default in a generic function