fix: Change the column identifier from string to text to avoid overflow (#9073)

Fixes: https://linear.app/chatwoot/issue/CW-3118/cannot-subscribe-to-notifications-on-microsoft-edge

Fix the issue with notifications in Microsoft Edge. The Edge push notification payload identifier has more than 255 characters. The API calls were failing due to this. This PR would fix the issue.

app/models/notification_subscription.rb

@@ -3,7 +3,7 @@
 # Table name: notification_subscriptions
 #
 #  id                      :bigint           not null, primary key
-#  identifier              :string
+#  identifier              :text
 #  subscription_attributes :jsonb            not null
 #  subscription_type       :integer          not null
 #  created_at              :datetime         not null