fix: incorrect preload link for multiple densities

[raggesilver]

NuxtImg did not add correct preload links for images that had multiple densities but only one size which caused the preload tag to load 1x images for devices with 2x pixel ratio. That is now fixed.

🔗 Linked issue

Resolves #1850

❓ Type of change

• 📖 Documentation (updates to the documentation or readme)
• 🐞 Bug fix (a non-breaking change that fixes an issue)
• 👌 Enhancement (improving an existing functionality)
• ✨ New feature (a non-breaking change that adds functionality)
• 🧹 Chore (updates to the build process or auxiliary tools and libraries)
• ⚠️ Breaking change (fix or feature that would cause existing functionality to change)

📚 Description

Do not require both sizes and densities to be set to generate imagesrcset. Take each of them into account.

[pkg-pr-new]

Open in StackBlitz

npm i https://pkg.pr.new/@nuxt/image@1851

commit: 4529248

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 0% with 5 lines in your changes missing coverage. Please review.

Project coverage is 53.51%. Comparing base (7e52488) to head (4529248).

Files with missing lines	Patch %	Lines
src/runtime/components/NuxtImg.vue	0.00%	5 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1851      +/-   ##
==========================================
+ Coverage   53.47%   53.51%   +0.04%     
==========================================
  Files          79       79              
  Lines        3755     3752       -3     
  Branches      377      377              
==========================================
  Hits         2008     2008              
+ Misses       1716     1713       -3     
  Partials       31       31              

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