RustFS gRPC GetMetrics deserialization panic enables remote DoS

RustFS is a distributed object storage system built in Rust. In versions 1.0.0-alpha.13 to 1.0.0-alpha.77, a malformed gRPC GetMetrics request causes get_metrics to unwrap() failed deserialization of metric_type/opts, panicking the handler thread and enabling remote denial of service of the metrics endpoint. This issue has been patched in version 1.0.0-alpha.78.