[RNMobile] Add Jetpack Tiled Gallery block square layout

[guarani]

Addresses wordpress-mobile/gutenberg-mobile#3874

Ports the Jetpack Tiled Gallery block to Mobile Gutenberg. It is part of a group of PRs, including this one. They are:

• [RNMobile] Add Jetpack Tiled Gallery block square layout #20831 (this PR)
• Add Jetpack Tiled Gallery block  wordpress-mobile/gutenberg-mobile#3875
• [RNMobile] Update userAgent override to be string instead of array WordPress/gutenberg#34308

Please note: This PR is currently a work-in-progress implementation and is incomplete (e.g. it does not yet contain changelog changes, PR checks will fail, etc).

Changes proposed in this Pull Request:

• Adds the Tiled Gallery block port for React Native
• The native mobile code diverges from the existing web implementation because we chose to use the InnerBlocks API, to follow the Gallery block's recent refactor to use InnerBlocks

Tiled Gallery block in native mobile Gutenberg	Inner Image block selected

Jetpack product discussion

TO-DO

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

TO-DO

Testing instructions:

TO-DO

[matticbot]

Caution: This PR has changes that must be merged to WordPress.com
Hello guarani! These changes need to be synced to WordPress.com - If you 're an a11n, please commandeer and confirm D65942-code works as expected before merging this PR. Once this PR is merged, please commit the changes to WP.com. Thank you!
This revision will be updated with each commit to this PR

[github-actions]

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🔴 Action required: Please add missing changelog entries for the following projects: projects/plugins/jetpack

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Jetpack plugin:

• Next scheduled release: September 7, 2021.
• Scheduled code freeze: August 30, 2021.

[guarani]

I'm closing this PR because all changes found in this PR have either been merged into the rnmobile/add/tiled-gallery-block branch via other PRs or are deemed no longer needed.