Fixes startup warning

src/lib/components/DateTimePicker.svelte

@@ -1,4 +1,6 @@
 <script lang="ts">
+  import { untrack } from 'svelte'
+
   let {
     value = $bindable(''),
     defaultTimeIndex = 36,
@@ -27,7 +29,7 @@
   let month = $state(today.getMonth())
   let day = $state(today.getDate())
   let year = $state(today.getFullYear())
-  let timeIndex = $state(defaultTimeIndex)
+  let timeIndex = $state(untrack(() => defaultTimeIndex))
 
   const daysInMonth = $derived(new Date(year, month + 1, 0).getDate())