Update `plot-benchmarks` to use Svelte 5.0.

Test: Ran the app locally.
Change-Id: I7f0ed08b67bce54af608919cd621d7eef00e76bd
diff --git a/development/plot-benchmarks/src/lib/Chart.svelte b/development/plot-benchmarks/src/lib/Chart.svelte
index edf6584..c1143bf 100644
--- a/development/plot-benchmarks/src/lib/Chart.svelte
+++ b/development/plot-benchmarks/src/lib/Chart.svelte
@@ -15,13 +15,6 @@
   export let isExperimental: boolean = false;
   export let showHistogramControls: boolean = false;
 
-  $: {
-    if ($chart) {
-      $chart.data = data;
-      $chart.update();
-    }
-  }
-
   // State
   let controlsDispatcher = createEventDispatcher<ControlsEvent>();
   let element: HTMLCanvasElement;
@@ -29,13 +22,20 @@
   let chart: Writable<Chart | null> = writable(null);
   let items: Writable<LegendItem[] | null> = writable(null);
 
+  $: {
+    if ($chart) {
+      $chart.data = data;
+      $chart.update();
+    }
+  }
+
   // Effects
   onMount(() => {
-    const onUpdate = (chart: Chart) => {
-      $chart = chart;
+    const onUpdate = (updated: Chart) => {
+      $chart = updated;
       // Bad typings.
-      const legend = chart.options.plugins?.legend as any;
-      $items = legend.labels.generateLabels(chart);
+      const legend = updated.options.plugins?.legend as any;
+      $items = legend.labels.generateLabels($chart);
     };
     const plugins = {
       tooltip: {
@@ -103,7 +103,7 @@

     </button>
   </div>
-  <canvas class="chart" bind:this={element} />
+  <canvas class="chart" bind:this={element}> </canvas>
   {#if showHistogramControls}
     <div class="controls">
       <label for="buckets">