Fix the 'test_remove_invalid_element_pseudo_selectors' test case

[Mamaduka]

What?

This a follow-up to #41786.

PR updates the 'test_remove_invalid_element_pseudo_selectors' test case's input value to match the test's intent.

Why?

The input and expected output were the same, so the test case wasn't testing invalid pseudo selector removal.

How?

I added an invalid pseudo selector to the input value.

Testing Instructions

PHP Unit tests are passing on CI.

npm run test:unit:php -- --filter WP_Theme_JSON_Gutenberg_Test

[github-actions]

Flaky tests detected in 7684a5b.
Some tests passed with failed attempts. The failures may not be related to this commit but are still reported for visibility. See the documentation for more information.

🔍 Workflow run URL: https://github.com/WordPress/gutenberg/actions/runs/3890987182
📝 Reported issues:

• [Flaky Test] should move the blocks down #39691 in specs/editor/various/block-editor-keyboard-shortcuts.test.js
• [Flaky Test] should write over selection #39938 in specs/editor/various/multi-block-selection.test.js

[getdave]

Thanks for the fix. How on earth did I write a test like that 🤦