{AzureBilling} fix #23097 (#23099)

* (AzureCXP) fixes #23097

(AzureCXP) fixes #23097

In this command, there is no documentation that shows where I can get the values for the "name" parameter. So this PR mentions to run the 'az billing period list' command to list the name of billing period' and then use this name in the 'az billing period show' command.

* Update _params.py

src/azure-cli/azure/cli/command_modules/billing/_params.py

@@ -13,7 +13,7 @@ def load_arguments(self, _):
         c.argument('name', options_list=['--name', '-n'], required=False, help='name of the invoice')
 
     with self.argument_context('billing period show') as c:
-        c.argument('billing_period_name', options_list=['--name', '-n'], help='name of the billing period')
+        c.argument('billing_period_name', options_list=['--name', '-n'], help='name of the billing period. Run the az billing period list command to list the name of billing period')
 
     with self.argument_context('billing enrollment-account show') as c:
         c.argument('name', options_list=['--name', '-n'], help='name of the enrollment account')