feat: Implement UI for Agent Bots in settings and remove CSML support (#11276)

- Add agent bots management UI in settings with avatar upload
- Enable agent bot configuration for all inbox types
- Implement proper CRUD operations with webhook URL support
- Fix agent bots menu item visibility in settings sidebar
- Remove all CSML-related code and features
- Add migration to convert existing CSML bots to webhook bots
- Simplify agent bot model and services to focus on webhook bots
- Improve UI to differentiate between system bots and account bots

## Video 





https://github.com/user-attachments/assets/3f4edbb7-b758-468c-8dd6-a9537b983f7d

---------

Co-authored-by: iamsivin <iamsivin@gmail.com>
Co-authored-by: Sivin Varghese <64252451+iamsivin@users.noreply.github.com>
Co-authored-by: Muhsin Keloth <muhsinkeramam@gmail.com>
Co-authored-by: Pranav <pranav@chatwoot.com>

app/javascript/dashboard/api/agentBots.js

@@ -1,9 +1,26 @@
+/* global axios */
 import ApiClient from './ApiClient';
 
 class AgentBotsAPI extends ApiClient {
   constructor() {
     super('agent_bots', { accountScoped: true });
   }
+
+  create(data) {
+    return axios.post(this.url, data, {
+      headers: { 'Content-Type': 'multipart/form-data' },
+    });
+  }
+
+  update(id, data) {
+    return axios.patch(`${this.url}/${id}`, data, {
+      headers: { 'Content-Type': 'multipart/form-data' },
+    });
+  }
+
+  deleteAgentBotAvatar(botId) {
+    return axios.delete(`${this.url}/${botId}/avatar`);
+  }
 }
 
 export default new AgentBotsAPI();