Prettier 2: Electric Boogaloo (#6113)

# Description of Changes
When I added Prettier formatting in #6052, my aim was to use just the
default settings in Prettier. Turns out, Prettier looks _really hard_
for any config files if it's not explicitly given one, which means that
if a developer has some sort of Prettier config file lying around on
their system, Prettier might find it and use it. Also, Prettier changes
its defaults based on stuff in `.editorconfig` without any good way of
disabling that behaviour explicitly in its config file.

To solve both of these issues, I've introduced a `.prettierrc` file
which sets Prettier's defaults explicitly, and then reformatted all our
code _again_ in Prettier's actual default settings. This should achieve
the aim of #6052 and remove the possibility for it breaking on different
dev computers.

frontend/src/core/extensions/accountLogout.ts

@@ -10,10 +10,16 @@ interface AccountLogoutDeps {
  * Proprietary/desktop builds override this file via path resolution.
  */
 export function useAccountLogout() {
-  return async ({ signOut, redirectToLogin }: AccountLogoutDeps): Promise<void> => {
+  return async ({
+    signOut,
+    redirectToLogin,
+  }: AccountLogoutDeps): Promise<void> => {
     try {
       if (typeof window !== "undefined") {
-        window.sessionStorage.setItem("stirling_sso_auto_login_logged_out", "1");
+        window.sessionStorage.setItem(
+          "stirling_sso_auto_login_logged_out",
+          "1",
+        );
       }
       await signOut();
     } finally {