Security update for elemental-system-agent

This update for elemental-system-agent fixes the following issue - CVE-2026-33186: google.golang.org/grpc: authorization bypass due to improper validation of the HTTP/2: path pseudo- header (bsc#1260277). Changes: - Update to version 0.3.16: * setup for immutable releases (#274) * align system-agent image publishing for signed releases (#270) * Bumo github.com/docker/cli to v29.2.0 and go.opentelemetry.io/otel to v1.43.0 * run go mod tidy in /test folder * Bump google.golang.org/grpc from 1.75.0 to 1.79.3 (bsc#1260277 CVE-2026-33186) * Bump github.com/docker/cli in /test * export CATTLE_NODE_NAME if SYSTEM_UPGRADE_NODE_NAME is set * use correct prefix for system-agent binary (#273) * checksum validation (#271) * Add `validate` subcommand for configuration validation (#250) * Update CODEOWNERS * Pin GH Actions to commit sha * chore: bump sles to 15.7 * Extend remote plan e2e tests * Fix agent restart issue and introduce constants * chore: bump go to v1.25 * Setup e2e test infrastructure * chores(deps): Bump k8s dependencies * Define linter rules * Fix CI failures * Introduce an extended Makefile * Switch workflows to use name makefile * Replace dapper with multi stage builds * Remove dapper scripts * Add multiple improvements for ignore files * fix: remove umask command from the system-agent unit-file * fix-system-agent-umask * [1.34] bumped dependencies for 1.34 support (#242) * Bump K8s patch level to 1.33.5 and Go patch level to 1.24.6 * fix: properly handle traps after unsuccessful SUC job execution * fix: do not unconditionally reset failure-counts * fix: remove resetFailureCountOnStartup, always reset failure counts on first start * un-rc wrangler and lasso * drop windows 2019 when running PR CI