feat: Support dark mode in login pages (#7420)

Co-authored-by: Sivin Varghese <64252451+iamsivin@users.noreply.github.com>

app/javascript/v3/views/auth/signup/Index.vue

@@ -0,0 +1,87 @@
+<template>
+  <div class="h-full w-full dark:bg-slate-900">
+    <div v-show="!isLoading" class="flex h-full">
+      <div
+        class="flex-1 min-h-[640px] inline-flex items-center h-full justify-center overflow-auto py-6"
+      >
+        <div class="px-8 max-w-[560px] w-full overflow-auto">
+          <div class="mb-4">
+            <img
+              :src="globalConfig.logo"
+              :alt="globalConfig.installationName"
+              class="h-8 w-auto block dark:hidden"
+            />
+            <img
+              v-if="globalConfig.logoDark"
+              :src="globalConfig.logoDark"
+              :alt="globalConfig.installationName"
+              class="h-8 w-auto hidden dark:block"
+            />
+            <h2
+              class="mb-7 mt-6 text-left text-3xl font-medium text-slate-900 dark:text-woot-50"
+            >
+              {{ $t('REGISTER.TRY_WOOT') }}
+            </h2>
+          </div>
+          <signup-form />
+          <div class="text-sm text-slate-800 dark:text-woot-50 px-1">
+            <span>{{ $t('REGISTER.HAVE_AN_ACCOUNT') }}</span>
+            <router-link class="text-link" to="/app/login">
+              {{
+                useInstallationName(
+                  $t('LOGIN.TITLE'),
+                  globalConfig.installationName
+                )
+              }}
+            </router-link>
+          </div>
+        </div>
+      </div>
+      <testimonials
+        v-if="isAChatwootInstance"
+        class="flex-1"
+        @resize-containers="resizeContainers"
+      />
+    </div>
+    <div
+      v-show="isLoading"
+      class="flex items-center justify-center h-full w-full"
+    >
+      <spinner color-scheme="primary" size="" />
+    </div>
+  </div>
+</template>
+
+<script>
+import { mapGetters } from 'vuex';
+import globalConfigMixin from 'shared/mixins/globalConfigMixin';
+import SignupForm from './components/Signup/Form.vue';
+import Testimonials from './components/Testimonials/Index.vue';
+import Spinner from 'shared/components/Spinner.vue';
+
+export default {
+  components: {
+    SignupForm,
+    Spinner,
+    Testimonials,
+  },
+  mixins: [globalConfigMixin],
+  data() {
+    return { isLoading: false };
+  },
+  computed: {
+    ...mapGetters({ globalConfig: 'globalConfig/get' }),
+    isAChatwootInstance() {
+      return this.globalConfig.installationName === 'Chatwoot';
+    },
+  },
+  beforeMount() {
+    this.isLoading = this.isAChatwootInstance;
+  },
+  methods: {
+    resizeContainers() {
+      this.isLoading = false;
+    },
+  },
+};
+</script>