BUG: The order of the items in edit event timeline schedule

## 🐛 Bug Report

### What went wrong?

On the edit even page, the Timeline section does not behave as expected when adding a new item to the schedule. When adding a new item to the timeline schedule, the date is saved as a date object rather than a string, which cannot be directly compared to what is fetched from the server in the string format.

### Expected Behavior

The order of timeline items stays the same as you add a new item.

### Actual Behavior

The order of the timeline changes on each title input change.
The date format displayed to the user is also different depending on the type of value passed to the component that renders the date. It's either as a string or an ISO formatted string.

### Steps to Reproduce Issue

If there are no objects in the timeline add a new item and save the changes. Then add a new item without saving the changes and try typing in the input field again. The order of the items should change on each input update.

#### Browser

Browser info:
Firefox

### Screenshots

Start by reproducing the edit event timeline issue in Firefox: add and save a timeline item, add another without saving, then type in its title while observing the order and displayed dates. Done means timeline items keep their order during input changes and dates use one consistent format.

Scritto dal modello di indicizzazione a partire dal testo della issue.