Fix for current_parsed_blocks value when block has inner blocks

[mkaz]

In ​https://github.com/WordPress/gutenberg/pull/26192 we refactored the block supports mechanism. It works by holding a global $current_parsed_blocks reference that it uses to determine the attributes that it needs to add to blocks.

However, when a block has inner blocks, that reference isn't updated so inner blocks end up inheriting the parent's properties (style and classes).

Related Gutenberg ticket: ​https://github.com/WordPress/gutenberg/pull/26291

[nosolosw]

This is being ported as part of ​https://github.com/WordPress/wordpress-develop/pull/626. Should we perhaps let that PR take care of the updating and close this patch?

[mkaz]

Closing per @nosolosw comment above that it will get ported as part of WP/Gutenberg release.