[RNMobile] Fix Tiled Gallery JS test failure

[guarani]

Fixes failing JS test that was introduced by a bug in https://github.com/Automattic/jetpack/pull/21767/files. The failing test is:

  FAIL extensions/blocks/tiled-gallery/layout/mosaic/test/index.js
    ● renders as expected
  
      TypeError: row.querySelectorAll is not a function
  
        58 | function getRowCols( row ) {
        59 | 	return Platform.select( {
      > 60 | 		web: () => Array.from( row.querySelectorAll( '.tiled-gallery__col' ) ),
           | 		                           ^
        61 | 		native: () => row,
        62 | 	} )();
        63 | }

Related:

• Fix Tiled Gallery JS test failure wordpress-mobile/gutenberg-mobile#4439

Changes proposed in this Pull Request:

• Bug fix for the Tiled Gallery on the web (this bug isn't on master, it's only on our feature branch).

Jetpack product discussion

p9ugOq-1Tb-p2

Does this pull request change what data or activity we track or use?

No, it does not.

Testing instructions:

Verify that the JS tests CI check passes. The "Code coverage" test may fail for different reasons, as long as it doesn't fail due to the above error.

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[guarani]

Summary of failing tests:

Tests / PHP tests: PHP 8.1 WP master (pull_request)

The PHP 8.1 test is optional (see experimental keyword here and here.

Linting / Changelogger use

We'll be adding the changelog in a future PR to merge the feature branch to master (see this comment).

wpcom — Could not cleanly apply this PR to synced wpcom files

This is fine to ignore for now since we're merging to a feature branch.

[SiobhyB]

LGTM, thanks for fixing this @guarani 🙇‍♀️