Feature: Add/Edit conversation labels (#488)

Co-authored-by: Pranav Raj S <pranavrajs@gmail.com>

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

@@ -1,5 +1,6 @@
 {
   "CONTACT_PANEL": {
+    "CONVERSATION_TITLE": "Conversation Details",
     "BROWSER": "Browser",
     "OS": "Operating System",
     "INITIATED_FROM": "Initiated from",
@@ -9,8 +10,11 @@
       "TITLE": "Previous Conversations"
     },
     "LABELS": {
-      "NO_RECORDS_FOUND": "There are no labels associated to this conversation.",
-      "TITLE": "Labels"
+      "TITLE": "Conversation Labels",
+      "UPDATE_BUTTON": "Update Labels",
+      "UPDATE_ERROR": "Couldn't update labels, try again.",
+      "TAG_PLACEHOLDER": "Add new label",
+      "PLACEHOLDER": "Search or add a label"
     }
   }
 }