Federate v25 - New setting is required to make SearchGuard work

To all the Siren Federate users,

From the release of Federate v25, a new setting is required to make SearchGuard work. The online documentation has been updated to reflect the same. See in the Breaking Changes section of the release notes here. The change is the node-level setting searchguard.allow_custom_headers: "siren.*" must be added to each node of the cluster