feat: migrate ItemsListInjection mixin

[lauramargar]

Pull request template

Migrate ItemsListInjection mixin.
The initial idea was to migrate all components that use this mixin and then remove it. The components involved are:

• ResultsList
• BannersList
• PromotedsList
• NextQueriesList

Motivation and context

• Dependencies. If any, specify:
• Open issue. If applicable, link: EMP-3792

Type of change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that causes existing functionality to not work as expected)
• Change requires a documentation update

What is the destination branch of this PR?

• Main
• Other. Specify:

How has this been tested?

Tests performed according to testing guidelines:

Checklist:

• My code follows the style guidelines of this project.
• I have performed a self-review on my own code.
• I have commented my code, particularly in hard-to-understand areas.
• I have made corresponding changes to the documentation.
• My changes generate no new warnings.
• I have added tests that prove my fix is effective or that my feature works.
• New and existing unit tests pass locally with my changes.

[joseacabaneros]

Why this subscription is only needed in this component and not the others? 🤔

[joseacabaneros]

I'm not sure if the DOM tree could interfere with styles. Anyway and for the time being, it seems the best option we have. Really good job here! 🎩

[diegopf]

I've found why the NoElement was a problem in the playground. It has to do with how slots are working in vue 3 in contrast with vue 2. We can discuss it tomorrow!