Fix single file upload display (#7221)

* Fix bug + add buggy story

* add changeset

* story fix

---------

Co-authored-by: gradio-pr-bot <gradio-pr-bot@users.noreply.github.com>
Co-authored-by: Hannah <hannahblair@users.noreply.github.com>

.changeset/red-squids-drop.md

@@ -0,0 +1,6 @@
+---
+"@gradio/file": patch
+"gradio": patch
+---
+
+fix:Fix single file upload display

js/file/FileUpload.stories.svelte

@@ -0,0 +1,64 @@
+<script context="module">
+	import { Template, Story } from "@storybook/addon-svelte-csf";
+	import { format } from "svelte-i18n";
+	import FileUpload from "./shared/FileUpload.svelte";
+	import { get } from "svelte/store";
+
+	export const meta = {
+		title: "Components/FileUpload",
+		component: FileUpload,
+		argTypes: {
+			value: {
+				control: "text",
+				description: "The URL or filepath (or list of URLs or filepaths)",
+				name: "value",
+				value: []
+			},
+			file_count: {
+				control: "radio",
+				options: ["single", "multiple"],
+				description: "Whether to allow single or multiple files to be uploaded",
+				name: "file_count",
+				value: "single"
+			}
+		}
+	};
+</script>
+
+<Template let:args>
+	<FileUpload {...args} i18n={get(format)} />
+</Template>
+
+<Story
+	name="Single File"
+	args={{
+		value: [
+			{
+				path: "cheetah.jpg",
+				orig_name: "cheetah.jpg",
+				url: "https://gradio-builds.s3.amazonaws.com/demo-files/ghepardo-primo-piano.jpg",
+				size: 10000
+			}
+		],
+		file_count: "single"
+	}}
+/>
+<Story
+	name="Multiple files"
+	args={{
+		value: Array(2).fill({
+			path: "cheetah.jpg",
+			orig_name: "cheetah.jpg",
+			url: "https://gradio-builds.s3.amazonaws.com/demo-files/ghepardo-primo-piano.jpg",
+			size: 10000
+		}),
+		file_count: "multiple"
+	}}
+/>
+<Story
+	name="No value"
+	args={{
+		value: null,
+		file_count: "multiple"
+	}}
+/>

js/file/shared/FileUpload.svelte

@@ -67,7 +67,7 @@
 	label={label || "File"}
 />
 
-{#if value && (Array.isArray(value) ? value.length > 0 : false)}
+{#if value && (Array.isArray(value) ? value.length > 0 : true)}
 	<ModifyUpload {i18n} on:clear={handle_clear} absolute />
 	<FilePreview {i18n} on:select {selectable} {value} {height} />
 {:else}