fix error display on submit in datePicker

packages/synapse-bridge/src/patterns/DatePicker/DatePicker.vue

@@ -30,6 +30,7 @@ export default defineComponent({
 		calendarValue: undefined as Date | undefined | [Date, Date] | [Date],
 		calendarIcon: mdiCalendar,
 		errorMessages: null as string[] | null,
+		isMounted: false,
 	}),
 	props: {
 		modelValue: String as PropType<string | null>,
@@ -127,6 +128,11 @@ export default defineComponent({
 			return dayjs(this.textFieldValue, this.dateFormat, true)
 		},
 	},
+	async mounted() {
+		await this.$nextTick(() => {
+			this.isMounted = true;
+		});
+	},
 	watch: {
 		modelValue: {
 			handler(newValue) {
@@ -179,6 +185,10 @@ export default defineComponent({
 				this.$nextTick(() => {
 					this.updateMessages()
 				})
+			} else if (!this.calendarValue && this.isMounted) {
+				this.$nextTick(() => {
+					this.updateMessages()
+				})
 			}
 		},
 	},