Do not display post link when the Post Type is not viewable

[imath]

The wp_block is a good example: when you create a new reusable block from the editor, the success notice and the publish panel should not display links to the saved reusable block as these links lead to nowhere on the front-end. This can concern any post type setting their public property to false.

Description

I've added checks on the viewable property of the Post Type to make sure links leading to nowhere are not displayed within the editor notices or Publish panel when this property is set to false.

How has this been tested?

1. I've tested my changes creating new reusable blocks from the Add New button of the reusable blocks management screen to check a not viewable post type has not front-end links displayed.
2. I've tested my changes with regular (& viewable) post type to check these changes had no impact on the viewable post type.

Gutenberg master / WordPress 5.0-beta3-20181106.024238

Screenshots

Without the changes, red arrows are showing the parts that the editor should not display for a not viewable post type.

With the changes, green arrows are showing how parts have been edited for the not viewable post types.

Types of changes

Bug fix (non-breaking change which fixes an issue)

Checklist:

• My code is tested.
• My code follows the WordPress code style.
• My code follows the accessibility standards.
• My code has proper inline documentation.

closes #8151

[danielbachhuber]

Related #8151

[youknowriad]

I was going to merge this and I noticed that it's already fixed in master but in a slightly different way (there's no post publish panel for these CPTs).

Closing, let me know if I missed anything here.