MNT: Do not write config on import

[pllim]

This functionality will be deprecated in astropy in a future release. See astropy/astropy#11497 and https://groups.google.com/g/astropy-dev/c/KVzPgeihxO8

[codecov]

Codecov Report

Merging #429 (fa5bae9) into develop (71f23fd) will increase coverage by 0.07%.
The diff coverage is n/a.

@@             Coverage Diff             @@
##           develop     #429      +/-   ##
===========================================
+ Coverage    74.33%   74.41%   +0.07%     
===========================================
  Files           18       18              
  Lines         6161     6145      -16     
===========================================
- Hits          4580     4573       -7     
+ Misses        1581     1572       -9     

Impacted Files	Coverage Δ
poppy/__init__.py	97.91% <ø> (+13.54%)	⬆️

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