Remove Navigation screen from experiments page

[getdave]

What?

📣 This is not a formal removal or ending of the Navigation Editor project. It is a stop gap whilst we consider the future of the project. See Why below.

As suggested in #40822 (comment) by @talldan, this PR removes the Navigation screen from the Gutenberg Experiments page. This means it can now only be accessed directly via URL.

Why?

Contributors are getting bug reports regarding this screen but it is not currently being actively maintained or worked on. This takes up time.

I decided against completely deleting the feature because there's been no official discussion or decision on that. However, this is a nice simple step that will help stem the flow of Issues being reported for a project which is not maintained.

How?

Removes the screen from the PHP which registers items on the Experiments page.

Testing Instructions

1. Goto Experiments page at http://localhost:8888/wp-admin/admin.php?page=gutenberg-experiments
2. Verify that the Navigation Editor experiment no longer appears.

Screenshots or screencast

[talldan]

Nice, thanks for doing that so quickly!

There might be some users who have the option already enabled and will be unable to turn it off with this change. I think this is the code that adds the wp admin menu entry:

gutenberg/lib/init.php

Lines 33 to 44 in df8647c

	if ( get_option( 'gutenberg-experiments' ) ) {
	if ( array_key_exists( 'gutenberg-navigation', get_option( 'gutenberg-experiments' ) ) ) {
	add_submenu_page(
	'gutenberg',
	__( 'Navigation (beta)', 'gutenberg' ),
	__( 'Navigation (beta)', 'gutenberg' ),
	'edit_theme_options',
	'gutenberg-navigation',
	'gutenberg_navigation_page'
	);
	}
	}

I wonder if it's worth doing something like this:

        // The navigation editor menu item is temporarily removed by hardcoding `false` here.
        // See https://github.com/WordPress/gutenberg/pull/40878 for more info.
	if ( false && get_option( 'gutenberg-experiments' ) ) {

What do you think?

[getdave]

Great thinking @talldan as always 🙇

[draganescu]

Aside from @talldan 's great suggestion this is good.

[getdave]

OK @talldan I've made the changes. What do you think?

[mrfoxtalbot]

@getdave, if the Navigation Screen has been removed, does that mean we could review and close pretty much all the open related issues?

[getdave]

@getdave, if the Navigation Screen has been removed, does that mean we could review and close pretty much all the open related issues?

I think that's reasonable.