refactor(email): tighten inbox setup flow

app/controllers/api/v1/accounts/inboxes_controller.rb

@@ -41,7 +41,7 @@ class Api::V1::Accounts::InboxesController < Api::V1::Accounts::BaseController
           name: inbox_name(channel),
           channel: channel
         }.merge(
-          permitted_params.except(:channel)
+          permitted_params.except(:channel, :imap_fetch_interval)
         )
       )
       @inbox.save!
@@ -192,7 +192,7 @@ class Api::V1::Accounts::InboxesController < Api::V1::Accounts::BaseController
   def permitted_params(channel_attributes = [])
     # We will remove this line after fixing https://linear.app/chatwoot/issue/CW-1567/null-value-passed-as-null-string-to-backend
     params.each { |k, v| params[k] = params[k] == 'null' ? nil : v }
-    params.permit(*inbox_attributes, channel: [:type, *channel_attributes])
+    params.permit(:imap_fetch_interval, *inbox_attributes, channel: [:type, *channel_attributes])
   end
 
   def channel_type_from_params