chore: Update availability status everywhere if the user changes the status from the account menu (#2581)

* add agent mixin

* apply agent mixin in components

* review fixes

* fix specs

app/javascript/dashboard/mixins/agentMixin.js

@@ -0,0 +1,35 @@
+import { mapGetters } from 'vuex';
+
+export default {
+  computed: {
+    assignableAgents() {
+      return this.$store.getters['inboxAssignableAgents/getAssignableAgents'](
+        this.inboxId
+      );
+    },
+    ...mapGetters({
+      currentUser: 'getCurrentUser',
+    }),
+    agentsList() {
+      const agents = this.assignableAgents || [];
+      return [
+        {
+          confirmed: true,
+          name: 'None',
+          id: 0,
+          role: 'agent',
+          account_id: 0,
+          email: 'None',
+        },
+        ...agents,
+      ].map(item =>
+        item.id === this.currentUser.id
+          ? {
+              ...item,
+              availability_status: this.currentUser.availability_status,
+            }
+          : item
+      );
+    },
+  },
+};