Spearhead: remove excess JS from the frontend

[sgomes]

Spearhead currently loads Gutenberg JS on the frontend, resulting in significantly reduced loading performance. This appears to be due to the wrong hook being used.

Changes proposed in this Pull Request:

• Change block extends to happen on enqueue_block_editor_assets instead of enqueue_block_assets

Related issue(s):

Fixes #7848

[github-actions[bot]]

Preview changes

I've detected changes to the following themes in this PR: Spearhead (Classic).

You can preview these changes by following the links below:

• Preview changes for Spearhead (Classic) (child of seedlet)

I will update this comment with the latest preview links as you push more changes to this PR. ⚠️ Note: The preview sites are created using WordPress Playground. You can add content, edit settings, and test the themes as you would on a real site, but please note that changes are not saved between sessions.

⚠️ Note: Child themes are dependent on their parent themes. You will have to install the parent theme as well for the preview to work correctly.

[sgomes]

Thank you for the quick review, @vcanales! 👍