Drop @vitejs/plugin-legacy (#3858)

config/vite.config.js

@@ -1,4 +1,3 @@
-import legacy from "@vitejs/plugin-legacy";
 import vue from "@vitejs/plugin-vue";
 import { defineConfig } from "vite";
 import visualizer from "rollup-plugin-visualizer";
@@ -24,9 +23,6 @@ export default defineConfig({
     plugins: [
         commonjs(),
         vue(),
-        legacy({
-            targets: [ "since 2015" ],
-        }),
         visualizer({
             filename: "tmp/dist-stats.html"
         }),