Checkmk Werk 13077: fix REST API ETag configuration option

ID: 13077 Title: fix REST API ETag configuration option Component: Core & setup Level: 1 Class: Bug fix Version: 2.1.0i1 The configuration option for the ETags, previously introduced in Werk 11938 did not show up in the global configuration setup GUI. This was due to a bug, which this Werk fixes. The ETag functionality can now be turned on/off through the "Global settings > Site Management > REST API: Use HTTP ETags for optimistic locking" configuration value.