Update gutenberg_get_template_hierarchy.

[jorgefilipecosta]

This PR updates gutenberg_get_template_hierarchy to include the enhancements made during the backport to the core.

Testing Instructions

Verify the unit tests pass with success.

[github-actions]

Flaky tests detected in 001178b.
Some tests passed with failed attempts. The failures may not be related to this commit but are still reported for visibility. See the documentation for more information.

🔍 Workflow run URL: https://github.com/WordPress/gutenberg/actions/runs/4078740573
📝 Reported issues:

• [Flaky Test] should insert block with the slash inserter when using multiple words #40301 in specs/editor/various/inserting-blocks.test.js