Do not create revisions for the GlobalStyles CustomPostType

[oandregal]

We use a CustomPostType to store user data for global styles. The CPT post_type is global-styles and the post name is wp-global-styles-<theme-stylesheet>.

In #30088 (comment) @jeyip shared that he was seeing revisions stored for the CPT.

We're not using these revisions yet, so we should look into how/whether we can prevent them from being created.

How to test

• Activate the TT1-blocks theme and go to the site editor.
• Update something in the global styles sidebar and save (e.g.: change the root background).
• Go to the database and sort the wp_posts table by the post_modified field in descending order.
• Verify that the user changes have updated the global styles CTP: wp-global-styles-tt1-blocks as post_name and that a revision was created as well (post_name along the lines of <post_type_id_of_global_styles_cpt>-revision-v1.

[oandregal]

Added it to the backlog at #20331

[oandregal]

There's #30133 to close this.

[mtias]

Mmm, even if we are not using them, I don't think we should stop creating them. It'd be nice once we add UI to manage them that they are there already. This is a free rollback feature for the most part.