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

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

app/javascript/v3/store/index.js

@@ -0,0 +1,10 @@
+import Vue from 'vue';
+import Vuex from 'vuex';
+import globalConfig from 'shared/store/globalConfig';
+
+Vue.use(Vuex);
+export default new Vuex.Store({
+  modules: {
+    globalConfig,
+  },
+});