Use the middleware key as the middleware id in the test renderer

[matt-gadd]

Type: feature

The following has been addressed in the PR:

• There is a related issue
• All code has been formatted with prettier as per the readme code style guidelines
• Unit or Functional tests are included in the PR

Description:
This should make it easier to test things that leverage the middleware id, by not using a uuid and instead using the middleware key itself which is unique enough for the widget under test.

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[codecov]

Codecov Report

Merging #859 (901999d) into master (ad846c0) will decrease coverage by 0.00%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #859      +/-   ##
==========================================
- Coverage   94.71%   94.71%   -0.01%     
==========================================
  Files         127      127              
  Lines        8085     8084       -1     
  Branches     1884     1884              
==========================================
- Hits         7658     7657       -1     
  Misses        427      427              

Impacted Files	Coverage Δ
src/testing/renderer.ts	97.32% <ø> (-0.02%)	⬇️

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