fix(components): handle null values in DatepickerWithValues

- Add null to date ref type to match props.modelValue type
- Convert Date to string before passing to parseDateOrString
- Add null coalescing for flatpickrDate assignment

frontend/src/components/date/DatepickerWithValues.vue

@@ -121,7 +121,7 @@ const showHowItWorks = ref(false)
 
 const flatpickrDate = ref('')
 
-const date = ref<string|Date>('')
+const date = ref<string|Date|null>('')
 
 watch(
 	() => props.modelValue,
@@ -129,9 +129,10 @@ watch(
 		date.value = newValue
 		// Only set the date back to flatpickr when it's an actual date.
 		// Otherwise flatpickr runs in an endless loop and slows down the browser.
-		const parsed = parseDateOrString(date.value, false)
+		const dateValueAsString = date.value instanceof Date ? date.value.toISOString() : date.value
+		const parsed = parseDateOrString(dateValueAsString, false)
 		if (parsed instanceof Date) {
-			flatpickrDate.value = date.value
+			flatpickrDate.value = date.value instanceof Date ? date.value.toISOString() : (date.value ?? '')
 		}
 	},
 )

frontend/vite.config.ts

@@ -26,6 +26,7 @@ const PREFIXED_SCSS_STYLES = `@use "sass:math";
 /*
 ** Configure sentry plugin
 */
+// @ts-ignore
 function getSentryConfig(env: ImportMetaEnv): ViteSentryPluginOptions {
 	return {
 		skipEnvironmentCheck: true,