Wire Swift runtime: negative LENGTH_DELIMITED length in skipGroup() crashes any protobuf-decoding service

Wire's Swift runtime Wire SPM/CocoaPods product, implemented by wire-runtime-swift did not reject a negative LENGTHDELIMITED field length while skipping an unknown protobuf group. A crafted 10-byte protobuf payload could cause ProtoReader.skipGroup to read a length-delimited field whose varint...