FTC: remove fixed width and HR

[igorschoester]

Context

Summary

This PR can be summarized in the following changelog entry:

• Fixes a bug where the First time configuration would not resize properly on smaller width screens.
• Fixes a bug where the First time configuration would have a double separator for the title and content.

Relevant technical choices:

Make indexation step responsive
The hardcoded width is preventing collapsing. But it was already moving the image below it.
So I really don't see a need for the width, instead lets try to take a similar amount of space if available.
But don't prevent it from being smaller.

Test instructions

Test instructions for the acceptance test before the PR gets merged

This PR can be acceptance tested by following these steps:

• Go to the First time configuration
• Play around with the screen size
• Verify it now shrinks properly and has no more horizontal scrolling
  • In particular it is regarding the SEO data optimization (first) step's description and image.

Relevant test scenarios

• Changes should be tested with the browser console open
• Changes should be tested on different posts/pages/taxonomies/custom post types/custom taxonomies
• Changes should be tested on different editors (Default Block/Gutenberg/Classic/Elementor/other)
• Changes should be tested on different browsers
• Changes should be tested on multisite

Test instructions for QA when the code is in the RC

• QA should use the same steps as above.

QA can test this PR by following these steps:

Impact check

This PR affects the following parts of the plugin, which may require extra testing:

• The FTC styling

UI changes

• This PR changes the UI in the plugin. I have added the 'UI change' label to this PR.

Other environments

• This PR also affects Shopify. I have added a changelog entry starting with [shopify-seo], added test instructions for Shopify and attached the Shopify label to this PR.

Documentation

• I have written documentation for this change. For example, comments in the Relevant technical choices, comments in the code, documentation on Confluence / shared Google Drive / Yoast developer portal, or other.

Quality assurance

• I have tested this code to the best of my abilities.
• During testing, I had activated all plugins that Yoast SEO provides integrations for.
• I have added unit tests to verify the code works as intended.
• If any part of the code is behind a feature flag, my test instructions also cover cases where the feature flag is switched off.
• I have written this PR in accordance with my team's definition of done.
• I have checked that the base branch is correctly set.

Innovation

• No innovation project is applicable for this PR.
• This PR falls under an innovation project. I have attached the innovation label.
• I have added my hours to the WBSO document.

Fixes https://github.com/Yoast/reserved-tasks/issues/295

[coveralls]

Pull Request Test Coverage Report for Build cca349042c8777c50a79ee74c3d59adb2668e630

Details

• 0 of 1 (0.0%) changed or added relevant line in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+13.5%) to 54.575%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
packages/js/src/first-time-configuration/tailwind-components/steps/indexation/indexation-step.js	0	1	0.0%

Totals
Change from base Build a4019d916ecde33fdc49ec99bba91f3498760793:	13.5%
Covered Lines:	29672
Relevant Lines:	54638

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💛 - Coveralls

[thijsoo]

CR + ACC 👍