protobufjs: Denial of service through unbounded Any expansion during JSON conversion

protobufjs compiles protobuf definitions into JavaScript (JS) functions. Prior to 7.6.1 and 8.4.1, protobufjs could recurse without a depth limit while converting decoded messages to plain objects or JSON. This affected generated toObject() conversion and the custom google.protobuf.Any JSON conversion path. A crafted protobuf binary payload containing deeply nested Any values could cause the JavaScript call stack to be exhausted during conversion to JSON. This vulnerability is fixed in 7.6.1 and 8.4.1.