Annotations: Editor isn't accessible

<!-- Please only use this template for submitting accessibility issues. This is a new feature area for Grafana that we want to improve. We have long way to go to really improve accessibility and would like your help to know where to start. --> **Steps to reproduce**: View a dashboard with annotations and hit the "edit" button in one of the annotations to open the editor. <img width="513" height="325" alt="Image" src="https://github.com/user-attachments/assets/a871361b-7460-4dd1-87d1-488245746c8c" /> **Actual Result**: The "description" field has no accessible label, and the "tags" field maybe doesn't have a label? If you click the label for either field, it doesn't focus the input, which is a giveaway that things aren't hooked up correctly. The tags input probably needs some aria attributes to make it a little more obvious that it's interactive, I think, although keyboard events do work. **Expected Result**: The fields inside this popover should be accessible and have labels, be tabbable back and forth, etc. **Relevant WCAG Criteria:** https://dequeuniversity.com/rules/axe/4.11/label **Environment**: - Grafana version: 12.4.0 - Data source type & version: n/a - User OS & Browser: Chrome - Others: n/a