chore: Custom Roles to manage permissions [ UI ] (#9865)

In admin settings, this Pr will add the UI for managing custom roles (
ref: https://github.com/chatwoot/chatwoot/pull/9995 ). It also handles
the routing logic changes to accommodate fine-tuned permissions.

---------

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

app/javascript/dashboard/i18n/locale/en/agentMgmt.json

@@ -18,7 +18,8 @@
       "STATUS": "Status",
       "ACTIONS": "Actions",
       "VERIFIED": "Verified",
-      "VERIFICATION_PENDING": "Verification Pending"
+      "VERIFICATION_PENDING": "Verification Pending",
+      "AVAILABLE_CUSTOM_ROLE": "Available custom role permissions"
     },
     "ADD": {
       "TITLE": "Add agent to your team",