chore: app group optimizations (#1027)

app/assets/javascripts/Utils/PreactUtils.ts

@@ -0,0 +1,10 @@
+import { render } from 'preact'
+
+/**
+ * Source: https://stackoverflow.com/questions/50946950/how-to-destroy-root-preact-node
+ * For some reason importing `import { unmountComponentAtNode } from 'preact/compat'` inside of app/index.tsx
+ * results in the app failing to compile.
+ */
+export function unmountComponentAtRoot(root: HTMLElement) {
+  render(null, root)
+}