Don't force dark mode on login page on cloud

I assume this was done because the cloud bg/header was designed for dark
mode and didn't look good in light mode. Since we aren't having the
cloud bg/header anymore, we can remove this.

src/lib/layout/unauthenticated.svelte

@@ -5,28 +5,12 @@
     import LoginLight from '$lib/images/login/login-light-mode.png';
     import { app } from '$lib/stores/app';
     import { user } from '$lib/stores/user';
-    import { onDestroy } from 'svelte';
 
     export let imgLight = LoginLight;
     export let imgDark = LoginDark;
 
-    let innerWidth = 0;
-    $: isMobile = innerWidth < 768;
-
-    const prevTheme = $app.theme;
-    $: if (isMobile) {
-        $app.theme = 'dark';
-    } else {
-        $app.theme = prevTheme;
-    }
-
-    onDestroy(() => {
-        $app.theme = prevTheme;
-    });
 </script>
 
-<svelte:window bind:innerWidth />
-
 <main class="grid-1-1 is-full-page" id="main">
     <section
         class="u-flex u-flex-vertical"