fix download button refresh bug

frontend/src/blocks/DownloadButton.vue

@@ -1,6 +1,7 @@
 <script setup lang="ts">
 import { useRemoteFileStore } from '@/stores.ts';
 import DownloadIcon from '@/icons/DownloadIcon.vue';
+import { computed } from 'vue';
 
 const props = defineProps<{
   file: dto.File
@@ -8,7 +9,7 @@ const props = defineProps<{
 
 const fileStore = useRemoteFileStore()
 
-const url = `${fileStore.serverUrl}/file/${props.file.id}`
+const url = computed(() => `${fileStore.serverUrl}/file/${props.file.id}`)
 </script>
 
 <template>