fix: crash in toggleViewsHints - debugDiv.appendChild (toolbar.js)

[mjomble]

Description
Fixes #9727

Checklist:

• Securely signed commits
• Component(s) with PHPDoc blocks, only if necessary or adds value (without duplication)
• Unit testing, with >80% coverage (no tests for JS)
• User guide updated
• Conforms to style guide

[mergeable]

Hi there, mjomble! 👋

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[michalsn]

I have confirmed this is working correctly.

Please add a changelog entry, see: https://github.com/codeigniter4/CodeIgniter4/pull/9736/files

[mjomble]

I noticed that both our PRs fix an Uncaught TypeError in toolbar.js, so I added a changelog line that refers to both bugs in plural.
When merging it all together, we can keep this one line instead of two very similar ones.

[michalsn]

Fair enough. Thank you.