Remove coupling of tests to cui

[matmair]

This PR upstreames changes from #8384 that can be taken now to decouple tests (and remove unneeded warnings)

[netlify]

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Name	Link
🔨 Latest commit	e9ba350
🔍 Latest deploy log	https://app.netlify.com/sites/inventree-web-pui-preview/deploys/67292e9d039a420008f15f61

[codecov]

Codecov Report

Attention: Patch coverage is 75.00000% with 3 lines in your changes missing coverage. Please review.

Project coverage is 84.35%. Comparing base (b4310bf) to head (e9ba350).

Files with missing lines	Patch %	Lines
src/backend/InvenTree/InvenTree/test_middleware.py	77.77%	2 Missing ⚠️
src/backend/InvenTree/build/tests.py	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #8389      +/-   ##
==========================================
- Coverage   84.47%   84.35%   -0.13%     
==========================================
  Files        1170     1168       -2     
  Lines       53456    52992     -464     
  Branches     1999     1882     -117     
==========================================
- Hits        45159    44703     -456     
- Misses       7769     7817      +48     
+ Partials      528      472      -56     

Flag	Coverage Δ
backend	85.84% <75.00%> (-0.07%)	⬇️

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