GSoC '24 - Dynamics Popup - Part 4

[kettogg]

This is the fourth part of the main pull request: https://github.com/musescore/MuseScore/pull/23038, which adds the preview of dynamic on hovering.

PR for part 1: https://github.com/musescore/MuseScore/pull/24125 PR for part 2: https://github.com/musescore/MuseScore/pull/24147 PR for part 3: https://github.com/musescore/MuseScore/pull/24152

• [x] I signed the CLA
• [x] The title of the PR describes the problem it addresses
• [x] Each commit's message describes its purpose and effects, and references the issue it resolves
• [x] If changes are extensive, there is a sequence of easily reviewable commits
• [x] The code in the PR follows the coding rules
• [x] There are no unnecessary changes
• [x] The code compiles and runs on my machine, preferably after each commit individually
• [x] I created a unit test or vtest to verify the changes I made (if applicable)