Update the Kubernetes Go packages in all Flux projects and run conformance for Kubernetes 1.34.0. This update requires Go 1.25 #5481

Repos subject to this upgrade:

• cli-utils
• pkg
• source-controller
• kustomize-controller
• notification-controller
• helm-controller
• image-reflector-controller
• image-automation-controller
• flux2
• terraform-provider-flux