fix: Update associations when a label is updated (#3046)

app/services/labels/update_service.rb

@@ -0,0 +1,35 @@
+class Labels::UpdateService
+  pattr_initialize [:new_label_title!, :old_label_title!, :account_id!]
+
+  def perform
+    tagged_conversations.find_in_batches do |conversation_batch|
+      conversation_batch.each do |conversation|
+        conversation.label_list.remove(old_label_title)
+        conversation.label_list.add(new_label_title)
+        conversation.save!
+      end
+    end
+
+    tagged_contacts.find_in_batches do |contact_batch|
+      contact_batch.each do |contact|
+        contact.label_list.remove(old_label_title)
+        contact.label_list.add(new_label_title)
+        contact.save!
+      end
+    end
+  end
+
+  private
+
+  def tagged_conversations
+    account.conversations.tagged_with(old_label_title)
+  end
+
+  def tagged_contacts
+    account.contacts.tagged_with(old_label_title)
+  end
+
+  def account
+    @account ||= Account.find(account_id)
+  end
+end