feat(ui5-time-picker): introduce open and close events (#9093)

As we introduced a declaritive property `open` which controls wether the value-help dialog of the `<ui5-timepicker>` is open or not, we are now introducing `open` and `close` events fired **after** the value-help dialog is opened or closed.

packages/main/src/TimePicker.ts

@@ -187,6 +187,18 @@ type TimePickerInputEventDetail = TimePickerChangeInputEventDetail;
 		},
 	},
 })
+/**
+ * Fired after the value-help dialog of the component is opened.
+ * @since 2.0.0
+ * @public
+ */
+@event("open")
+/**
+ * Fired after the value-help dialog of the component is closed.
+ * @since 2.0.0
+ * @public
+ */
+@event("close")
 class TimePicker extends UI5Element implements IFormInputElement {
 	/**
 	 * Defines a formatted time value.
@@ -380,6 +392,11 @@ class TimePicker extends UI5Element implements IFormInputElement {
 
 	onResponsivePopoverAfterClose() {
 		this.open = false;
+		this.fireEvent("close");
+	}
+
+	onResponsivePopoverAfterOpen() {
+		this.fireEvent("open");
 	}
 
 	/**

packages/main/src/TimePickerPopover.hbs

@@ -9,6 +9,7 @@
 	_hide-header
 	hide-arrow
 	@ui5-close="{{onResponsivePopoverAfterClose}}"
+	@ui5-open="{{onResponsivePopoverAfterOpen}}"
 	@wheel="{{_handleWheel}}"
 	@keydown="{{_onkeydown}}"
 >