### Steps to reproduce

1. Go to an existing dynamic meeting or create a new one
2. Add a new work package item
3. Without selecting a work package, go to the duration field instead and type a value
4. Click "Save"

### What is the buggy behavior?

* The save button is active even when no work package is selected yet
* A completely unrelated error is displayed at the top when "Save" is clicked without selecting a WP ("This meeting is not editable anymore.")

### What is the expected behavior?

1. Begin of the insertion~~TheEnd of the insertion Begin of the deletion TheEnd of the deletion save button is inactive until a work package is Begin of the insertionselected~~End of the insertion Begin of the deletion selectedEnd of the deletion
2. It is not possible to save a work package agenda item without selecting a work package first Begin of the insertion
1. There is a validation error: "Work package can't be blank."End of the insertion

### Screenshots and other files

<img class="op-uc-image op-uc-image_inline" src="/api/v3/attachments/76321/content">

### Environment information

OpenProject 13.1
Edge
Core build: f53dd7934b
Product version: 3a8dcd11

**Browser**

* [ ] Chrome
* [x] Firefox
* [ ] Safari
* [ ] Mobile Safari
* [ ] Other (please specify)

**Language**

EN