Widgets: Remove unused variables in widget toggle handler

[huzaifaalmesbah]

Ticket https://core.trac.wordpress.org/ticket/27307

Description

This PR refreshes and cleans up src/js/_enqueues/admin/widgets.js by removing unused variables (css, targetWidth, widgetWidth, margin) from the click.widgets-toggle event handler.

Related patch: https://core.trac.wordpress.org/attachment/ticket/27307/27307.diff

How to test

1. Apply the patch / PR and run npm run build to ensure JavaScript compiles without errors.
2. Install and activate the Classic Widgets plugin.
3. Navigate to Appearance → Widgets (Classic interface) in the WordPress admin.
4. Add the following widgets to a sidebar:
   • Text
   • Custom HTML
   • RSS
5. Toggle widgets open and closed to confirm:
   • No JavaScript console errors occur
   • Widget toggle behavior works as expected
6. Resize the browser window to smaller widths (or zoom the browser) and verify:
   • Widgets remain within the sidebar container
   • No horizontal overflow occurs

[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 huzaifaalmesbah, mukesh27.

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

[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.

[mukeshpanchal27]

JS error that needs to fix:

src/js/_enqueues/admin/widgets.js
     31 |            isRTL = !! ( 'undefined' !== typeof isRtl && isRtl );
                     ^ 'isRTL' is defined but never used.

[huzaifaalmesbah]

@mukeshpanchal27 Thanks for catching this.
I’ve removed the unused isRTL variable. Please check now.