Block editor: [Backport] Make fit text work with the interativity API.

[jorgefilipecosta]

Backports: WordPress/gutenberg#72923
Backports the required core changes to make fit text work correctly with the interactivity API.

Fit text did not work after navigating to a page using the Interactivity API router. When users navigated to a post via client-side navigation (e.g., in a Query block with pagination), fit text blocks would not recalculate their font sizes, appearing either too large or too small.

This occurred because the fit text initialization only ran on the window.load event, which doesn't fire during client-side navigation.

This PR refactors fit text front end to be an interactivity api first implementation, using an interactivity api init event instead of a window load event.

Ticket: https://core.trac.wordpress.org/ticket/64210

[github-actions]

The following accounts have interacted with this PR and/or linked issues. I will continue to update these lists as activity occurs. You can also manually ask me to refresh this list by adding the props-bot label.

Core Committers: Use this line as a base for the props when committing in SVN:

Props jorgefilipecosta, mukesh27.

To understand the WordPress project's expectations around crediting contributors, please review the Contributor Attribution page in the Core Handbook.

[mukeshpanchal27]

Q: Do we need to check if the block has the fitText attribute before setting it? Otherwise, this logic might apply the attribute to all block content elements, not just the ones that support fitText.

[jorgefilipecosta]

Hi @mukeshpanchal27, we are checking if the block has fittext attribute on the condition above: if ( ! empty( $block['attrs']['fitText'] ) && ! is_admin() ) {.

[github-actions]

Test using WordPress Playground

The changes in this pull request can previewed and tested using a WordPress Playground instance.

WordPress Playground is an experimental project that creates a full WordPress instance entirely within the browser.

Some things to be aware of

• The Plugin and Theme Directories cannot be accessed within Playground.
• All changes will be lost when closing a tab with a Playground instance.
• All changes will be lost when refreshing the page.
• A fresh instance is created each time the link below is clicked.
• Every time this pull request is updated, a new ZIP file containing all changes is created. If changes are not reflected in the Playground instance,
  it's possible that the most recent build failed, or has not completed. Check the list of workflow runs to be sure.

For more details about these limitations and more, check out the Limitations page in the WordPress Playground documentation.

Test this pull request with WordPress Playground.

[github-actions]

A commit was made that fixes the Trac ticket referenced in the description of this pull request.

SVN changeset: 61145
GitHub commit: 350d286

This PR will be closed, but please confirm the accuracy of this and reopen if there is more work to be done.