agent-platform release v4.81.1

Fixed

• A retried uninstall runs the serving teardown again without failing once the bundled engine has removed Flux (giantswarm/agent-platform#527). The <release>-serving-teardown hook deleted its two child HelmReleases unconditionally; on a retry after the engine’s teardown the HelmRelease API is gone, and every attempt failed with the server doesn't have a resource type "helmreleases", so the uninstall could not be retried. Without the API there is no child release left to order: the hook skips the two deletes and still frees any remaining config.