feat: Ability to lock to single conversation (#5881)

Adds the ability to lock conversation to a single thread for Whatsapp and Sms Inboxes when using outbound messages.

demo: https://www.loom.com/share/c9e1e563c8914837a4139dfdd2503fef

fixes: #4975

Co-authored-by: Nithin David <1277421+nithindavid@users.noreply.github.com>

app/javascript/dashboard/store/modules/contactConversations.js

@@ -89,7 +89,19 @@ export const mutations = {
   },
   [types.default.ADD_CONTACT_CONVERSATION]: ($state, { id, data }) => {
     const conversations = $state.records[id] || [];
-    Vue.set($state.records, id, [...conversations, data]);
+
+    const updatedConversations = [...conversations];
+    const index = conversations.findIndex(
+      conversation => conversation.id === data.id
+    );
+
+    if (index !== -1) {
+      updatedConversations[index] = { ...conversations[index], ...data };
+    } else {
+      updatedConversations.push(data);
+    }
+
+    Vue.set($state.records, id, updatedConversations);
   },
   [types.default.DELETE_CONTACT_CONVERSATION]: ($state, id) => {
     Vue.delete($state.records, id);