Use support align for image block

[spacedmonkey]

Description

Use support align for image block instead of implementing manually.

Fixes #13780
Related #17799

Checklist:

• My code is tested.
• My code follows the WordPress code style.
• My code follows the accessibility standards.
• My code has proper inline documentation.
• I've included developer documentation if appropriate.

[spacedmonkey]

The issue seems to be this in the tests

- <div class="wp-block-image"><figure class="alignleft is-resized"><img src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAACklEQVR4nGMAAQAABQABDQottAAAAABJRU5ErkJggg==" alt="" width="100" height="100"/></figure></div>

+ <div class="wp-block-image alignleft"><figure class="alignleft is-resized"><img src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAACklEQVR4nGMAAQAABQABDQottAAAAABJRU5ErkJggg==" alt="" width="100" height="100"/></figure></div>

It seems after the change, the wrapping div on longer has the alignment classes. Not sure why this is the case.

[earnjam]

Based on @youknowriad's comment on the linked issue, it appears this isn't really feasible right now.

There is also a lot of discussion about rethinking the approach to block alignment as a whole in #20650.

In light of that and this PR being outdated now, @spacedmonkey are you ok with closing this in favor of future work based on the outcomes of discussions in #20650?

[spacedmonkey]

Happy to close this