feat(datetime): ionChange will only emit from user committed changes (#26083)

resolves #20873 resolves #24452

BREAKING CHANGE

- `ionChange` is no longer emitted when the `value` property of `ion-datetime` is modified externally. `ionChange` is only emitted from user committed changes, such as clicking or tapping a date.

- Datetime no longer automatically adjusts the `value` property when passed an array and `multiple="false"`. Developers should update their apps to ensure they are using the API correctly.

core/src/components/datetime-button/datetime-button.tsx

@@ -126,7 +126,7 @@ export class DatetimeButton implements ComponentInterface {
        * text in the buttons.
        */
       this.setDateTimeText();
-      addEventListener(datetimeEl, 'ionChange', this.setDateTimeText);
+      addEventListener(datetimeEl, 'ionValueChange', this.setDateTimeText);
 
       /**
        * Configure the initial selected button