Fix incorrect nesting of buttons within a button

[talldan]

Description

Fixes #9033.

The DotTip component renders buttons, so nesting it within another button was causing invalid DOM nesting. This PR makes the DotTip and the Button siblings and both children of a new parent div element. DotTip requires this parent div element to position itself in the right place.

Since #16315 (comment) proposes to remove DotTips at some point, I've left a comment to ensure the wrapping div is removed when that work is carried out.

Screenshots

How has this been tested?

1. Go the editor options and enable Tips.
2. For the first three tips, click on 'See Next Tip'
3. When the forth tip appears ('Finished Writing?'), check the console in the dev tools.
4. Confirm that a Warning: validateDOMNesting(...): <button> cannot appear as a descendant of <button>. message does not appear in the console.

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.
• I've included developer documentation if appropriate.

[pento]

👍🏻 This fixes the warning for me!