Elastic Cloud Enterprise 2.9.1

This release of Elastic Cloud Enterprise contains bug fixes and a documentation improvement.

Filesystem permissions in ECE docker image. Fixes some filesystem permissions in ECE docker image, preventing the user from generating diagnostics and logs with Prepare Diagnostics Bundle and Prepare Logs buttons, when the host’s user is not elastic with uid 1000.

Set ALLOCATOR_RUNNER_REGION on ECE upgrade to 2.9.1. Fixes a bug where, after upgrading from specific ECE versions, container-task-service failed to boot.

Fix SSO 500 error. In ECE 2.9.0, some failure scenarios for deployments can lead to an inconsistent state where any further attempts to modify a deployment result in an error similar to "The following security realms are not matched across Elasticsearch and stateless resources: [cloud-saml-type-id]". In ECE 2.9.1, any inconsistent SSO security realm configuration due to previous failures will no longer cause this error.

Documentation on port 9400 for CCR/CCS. Add port 9400 to ECE Proxy documentation for enablement of transport passthrough for CCR/CCS.