Cleanup test files copied over the host application

[kennyadsl]

Summary

There were multiple inconsistencies and outdated code. Please read commit by commit for more details.

Checklist

Check out our PR guidelines for more details.

The following are mandatory for all PRs:

• [ ] I have written a thorough PR description.
• [ ] I have kept my commits small and atomic.
• [ ] I have used clear, explanatory commit messages.

The following are not always needed:

• 📖 I have updated the README to account for my changes.
• 📑 I have documented new code with YARD.
• 🛣️ I have opened a PR to update the guides.
• ✅ I have added automated tests to cover my changes.
• 📸 I have attached screenshots to demo visual changes.

[codecov[bot]]

Codecov Report

Merging #350 (dc83686) into main (09c253e) will increase coverage by 0.02%. The diff coverage is 96.77%.

@@            Coverage Diff             @@
##             main     #350      +/-   ##
==========================================
+ Coverage   97.28%   97.31%   +0.02%     
==========================================
  Files         189      187       -2     
  Lines        4526     4501      -25     
==========================================
- Hits         4403     4380      -23     
+ Misses        123      121       -2     

Impacted Files	Coverage Δ
template.rb	85.13% <ø> (ø)
.../spec/support/solidus_starter_frontend/capybara.rb	70.58% <ø> (-0.85%)	:arrow_down:
.../support/solidus_starter_frontend/system/assets.rb	100.00% <ø> (ø)
...olidus_starter_frontend/system/checkout_helpers.rb	95.83% <95.83%> (ø)
templates/spec/system/address_spec.rb	100.00% <100.00%> (ø)
...plates/spec/system/authentication/checkout_spec.rb	100.00% <100.00%> (ø)
templates/spec/system/checkout_spec.rb	100.00% <100.00%> (ø)
templates/spec/system/coupon_code_spec.rb	100.00% <100.00%> (ø)
...emplates/spec/system/first_order_promotion_spec.rb	100.00% <100.00%> (ø)
...lates/spec/system/free_shipping_promotions_spec.rb	100.00% <100.00%> (ø)
... and 1 more

... and 1 file with indirect coverage changes

:mega: We’re building smart automated test selection to slash your CI/CD build times. Learn more

[kennyadsl]

@elia @waiting-for-dev everything addressed, waiting for the CI before merging, thanks!