Display tooltip for "Copy to Clipboard" button

## What does this MR do?

Add a tooltip to the "Copy to Clipboard" button.

## Are there points in the code the reviewer needs to double check?

Nope.

## Why was this MR needed?

There was no tooltip.

## What are the relevant issue numbers?

fixes #19640, #19682

## Screenshots

(wrong cursor is the fault of my screenshot program)

![after](/uploads/6b89790fa3a32b06b115ef1461cbcd86/after.png)


See merge request !5164