chore: Enable Participating tab for conversations (#11714)

## Summary

This PR enables the **Participating** conversation view in the main
sidebar and keeps the behavior aligned with existing conversation views.

## What changed

- Added **Participating** under Conversations in the new sidebar.
- Added a guard in conversation realtime `addConversation` flow so
generic `conversation.created` events are not injected while the user is
on Participating view.
- Added participating route mapping in conversation-list redirect helper
so list redirects resolve correctly to `/participating/conversations`.

## Scope notes

- Kept changes minimal and consistent with current `develop` behavior.
- No additional update-event filtering was added beyond what existing
views already do.

---------


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

app/javascript/dashboard/store/modules/conversations/actions.js

@@ -6,6 +6,7 @@ import { createPendingMessage } from 'dashboard/helper/commons';
 import {
   buildConversationList,
   isOnMentionsView,
+  isOnParticipatingView,
   isOnUnattendedView,
   isOnFoldersView,
 } from './helpers/actionHelpers';
@@ -371,6 +372,7 @@ const actions = {
       !hasAppliedFilters &&
       !isOnFoldersView(rootState) &&
       !isOnMentionsView(rootState) &&
+      !isOnParticipatingView(rootState) &&
       !isOnUnattendedView(rootState) &&
       isMatchingInboxFilter
     ) {
@@ -395,6 +397,7 @@ const actions = {
     const {
       meta: { sender },
     } = conversation;
+
     commit(types.UPDATE_CONVERSATION, conversation);
 
     dispatch('conversationLabels/setConversationLabel', {