Disable polling of config parameters and update in a separate loop

[GDYendell]

Some tweaks to the FastCS core could make this a bit neater, but it works for now.

[codecov]

Codecov Report

Attention: 38 lines in your changes are missing coverage. Please review.

Comparison is base (a5b2021) 41.33% compared to head (7d0fbd9) 39.56%.
Report is 2 commits behind head on main.

Files	Patch %	Lines
src/eiger_fastcs/eiger_controller.py	35.41%	31 Missing ⚠️
src/eiger_fastcs/__main__.py	30.00%	7 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #18      +/-   ##
==========================================
- Coverage   41.33%   39.56%   -1.78%     
==========================================
  Files           3        3              
  Lines         150      182      +32     
==========================================
+ Hits           62       72      +10     
- Misses         88      110      +22     

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[GDYendell]

I need to remind myself if there is a good reason that the current logic is complicated and if we should just clear the set and let it fill up again while fetching. I think if the same parameter is added again, we can't be sure if we updated before or after, so we should just update it again.

[TBThomas56]

Gary - "Is a good reason that the current logic is complicated and if we should just clear the set and let it fill up again while fetching. I think if the same parameter is added again, we can't be sure if we updated before or after, so we should just update it again."