[5.x]: The UX for copying entries is confusing

What happened?

Description

When you copy an entry, you get a toast notification that is styled slightly different from regular notifications:

This toast notification pops up on every page load until it's dismissed, or the copied entry is pasted. Dismissing this toast notification also cancels the copy action and prevents you from pasting the entry. This is confusing for multiple reasons:

• It's annoying that the notification pops up on every page load, obscuring part of the screen. This feels like a bug, because no other notifications do this.
• The notifications in the lower right are usually informative and don't hold any state. It's not apparent that clicking the X also cancels the copy/paste action. It does say cancel, but that's easy to miss. And clicking the X at the upper right of notifications to dismiss them is a learned behavior.
• There's no way to get rid of the notification without also cancelling the copy/paste.
• I can't think of any precedent for a clipboard requiring a UI element that's constantly visible on the screen with no way to hide it, so it's not easy to grasp and not intuitive.

Suggested fix

• Bring the pop-up in line with other notifications: Have it pop up once and disappear according to the Notification Duration profile setting. Don't show it again on subsequent page loads.
• If you still want to provide a way to cancel the copy/paste action, move that to either the ellipsis menu next to the copy button, or as a secondary button next to the Paste entry button.

Craft CMS version

5.9.17

PHP version

No response

Operating system and version

No response

Database type and version

No response

Image driver and version

No response

Installed plugins and versions

Start by tracing the entry-copy toast, its persistence across page loads, and the copy, cancel, and Paste entry controls in the CMS UI. Compare the behavior with the Notification Duration profile setting; done means the toast follows that duration, does not reappear on later page loads, and cancellation remains available without making dismissal cancel the copy action.