Enqueued scripts are not printed on validation screens in WP 4.9

[westonruter]

Bug Description

When testing in WP 4.9, I noticed that the Details failed to expand the error info on the Validated URL screen:

It's not just that, as the search box doesn't work and the filter doesn't do anything. I believe there is a script dependency present which doesn't exist in 4.9. I tried registering the polyfills:

diff --git a/includes/validation/class-amp-validated-url-post-type.php b/includes/validation/class-amp-validated-url-post-type.php
index d018c774c..066332dfd 100644
--- a/includes/validation/class-amp-validated-url-post-type.php
+++ b/includes/validation/class-amp-validated-url-post-type.php
@@ -2127,6 +2127,9 @@ public static function enqueue_edit_post_screen_scripts() {
 			return;
 		}
 
+		/** This action is documented in includes/class-amp-theme-support.php */
+		do_action( 'amp_register_polyfills' );
+
 		// Eliminate autosave since it is only relevant for the content editor.
 		wp_dequeue_script( 'autosave' );

But this caused errors in the console:

In addition to the Validated URL screen, I'm also seeing that the scripts are not printed on the AMP Validated URLs screen, as clicking the tooltips aren't working:

This is also the case on the Error Index screen:

This is very low priority given the very old WP version.

Expected Behaviour

The UI should work as expected.

Screenshots

No response

PHP Version

No response

Plugin Version

2.2

AMP plugin template mode

Standard, Transitional, Reader

WordPress Version

No response

Site Health

No response

Gutenberg Version

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OS(s) Affected

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Browser(s) Affected

No response

Device(s) Affected

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Acceptance Criteria

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Implementation Brief

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QA Testing Instructions

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Demo

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Changelog Entry

No response

[westonruter]

I think we should just prevent users access to validation screens in WP<5.6.

[delawski]

QA Passed

✅ The validation screens are not accessible on WP<5.6.

WP 4.9	WP 5.5	WP 5.6