Improve the static vs dynamic rendering comment in the block tutorial.

[ndiego]

This is a minor tweak that improves the note about static vs. dynamic rendering in the new tutorial in the Block Editor Handbook.

[github-actions]

Flaky tests detected in 18f8152.
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/7279884878
📝 Reported issues:

• [Flaky Test] Should show Columns block only if selected blocks are between limits (1-6) #40369 in specs/editor/various/block-switcher.test.js