Open story export instructions in a new window

[westonruter]

Summary

• Make export instructions open in a new window when clicked in the editor as well.

Amends #4219; see #4202.

Checklist

• My pull request is addressing an open issue (please create one otherwise).
• My code is tested and passes existing tests.
• My code follows the Engineering Guidelines (updates are often made to the guidelines, check it out periodically).

[amedina]

Ship it!

[westonruter]

• Make export instructions open in a new window when clicked in the editor as well.

I see no way to open editor notices in a new window:

https://github.com/WordPress/gutenberg/blob/f96c3d478caa423017354a72032af3a3bfb517a9/packages/notices/src/store/actions.js#L11-L18

[pierlon]

@westonruter Here's one way to open a new window in the editor:

--- includes/options/class-amp-options-manager.php	(revision f77530f809c88cea6310d3d669119e0a710e3b8b)
+++ includes/options/class-amp-options-manager.php	(date 1581284825580)
@@ -621,8 +621,9 @@
 								isDismissible: false,
 								actions: [
 									{
-										url: 'https://amp-wp.org/documentation/amp-stories/exporting-stories/',
 										label: %s,
+										className: 'is-link', // to make the <button> look like a link
+										onClick: () => window.open(\"https://amp-wp.org/documentation/amp-stories/exporting-stories/\")
 									},
 								],
 						    }

[csossi]

Verified in QA