Re-enable passing post_id query arg for Server Side Rendering (#31786)

[bobbingwide]

Description

A change in PR #29246 altered a test so that it always failed.
It was testing typeof currentPostId.id which was undefined; in the block editor currentPostId is an integer.

Blocks which were Server Side Rendered and relied on the post_id being passed in the REST request were failing to return anything. They still worked when rendered for the front end.

I deleted three characters: .id.

How has this been tested?

• In a local development environment with the sb-children-block plugin.
• Tested in the block editor - see screenshot
• Tested in the site editor

Screenshots

Types of changes

Fixes a regression introduced in Gutenberg 10.4.0 by PR #29246

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).

[bobbingwide]

Here's the screen capture of the Site editor. I changed the Depth parameter. The Request URL doesn't contain the post_id query arg. The block returns an empty list since it has no post parent to find the children of.

[Mamaduka]

Looks good to me ✅

Thanks for fixing this @bobbingwide.