feat(trezorlib): allow encoding of protobuf messages without wire type

[no changelog]

python/src/trezorlib/mapping.py

@@ -68,6 +68,16 @@ class ProtobufMapping:
         protobuf.dump_message(buf, msg)
         return wire_type, buf.getvalue()
 
+    def encode_without_wire_type(self, msg: protobuf.MessageType) -> bytes:
+        """Serialize a Python protobuf class.
+
+        Returns the byte representation of the protobuf message.
+        """
+
+        buf = io.BytesIO()
+        protobuf.dump_message(buf, msg)
+        return buf.getvalue()
+
     def decode(self, msg_wire_type: int, msg_bytes: bytes) -> protobuf.MessageType:
         """Deserialize a protobuf message into a Python class."""
         cls = self.type_to_class[msg_wire_type]