Retry failed save and publish requests

[bastianallgeier]

Description

The model views will now show a "Retry" dialog when a save or publish request failed.

The methods will be executed again after clicking the "Try again" button.

Summary of changes

• New panel.content.closeRetryDialog() method
• New panel.content.retry() method

Additional context

The easiest way to test this is with the following steps.

1. Add this to the Kirby\Api\Controller\Changes class at the beginning of the save method:

if ($input === ['error' => true]) {
	throw new \Exception('Something went wrong');
}

2. Open the browser console and check both dialog versions like this:

// to show the retry dialog for failed save requests
panel.content.save({error: true});
// to show the retry dialog for failed publish requests
panel.content.publish({error: true});

Changelog

Fixes

• Fixed footer margin in dialogs if the cancelButton property is a string or object instead of a boolean.

Enhancements

• New retry dialog if changes cannot be saved or published.

For review team

• Add lab and/or sandbox examples (wherever helpful)
• Add changes & docs to release notes draft in Notion

[afbora]

Works great for me 👍 Also I couldn't see a discard changes issue for this PR.