Fix missing default align-items when items are oriented vertically in flex layout

[ndiego]

Description

This PR is an alternative approach to #37986, which actually fixes the root issue. Thanks @ntsekouras for spotting this!

For blocks that support the ability to orient items vertically, by default there is no justifyContent attribute applied. In the Editor, when there is no attribute we are applying align-items: flex-start as a default. On the frontend however, there is no default which leads to some rendering errors, particularly with the Social Icons block. This PR adds align-items: flex-start to the frontend when there is no justifyContent attribute and the block is meant to be oriented vertically.

How has this been tested?

1. Use Twenty Twenty-Two with Gutenberg 12.4 RC1 and WordPress 5.9 RC3
2. Add the Social Icons block with a couple Social Icons
3. Orient the block vertically. See that it displays correctly in the Editor
4. Switch to the Frontend and see that with this PR the icons display correctly as well, without this PR they render like the screenshots below

Screenshots

Without this PR

With this PR

Types of changes

Checklist:

• My code is tested.
• My code follows the WordPress code style.
• My code follows the accessibility standards.
• I've tested my changes with keyboard and screen readers.
• My code has proper inline documentation.
• I've included developer documentation if appropriate.
• I've updated all React Native files affected by any refactorings/renamings in this PR (please manually search all *.native.js files for terms that need renaming or removal).
• I've updated related schemas if appropriate.

[ndiego]

@ntsekouras I created a separate PR for the correct fix you highlighted in #37986. This seems to work like a charm. Let me know what you think. If this is the correct course, I will close out the other PR in favor of this one.

[ntsekouras]

This looks good! Thanks @ndiego 💯

[ndiego]

Awesome, thanks for the review! 🎉