Make a Merge() call allow not-yet-recognized new fields in P4Info files

This is helpful when p4c adds new P4Info fields to the P4Info files it
generates, but the consumers have not yet all been updated to
recognize them.  The most recent example of this in 2024-Aug is the
initial_default_action field of Table messages.

Signed-off-by: Andy Fingerhut <[email protected]>

Author: jafingerhut

p4runtime_sh/p4runtime.py

@@ -289,7 +289,7 @@ def set_fwd_pipe_config(self, p4info_path, bin_path):
         with open(p4info_path, 'r') as f1:
             with open(bin_path, 'rb') as f2:
                 try:
-                    google.protobuf.text_format.Merge(f1.read(), req.config.p4info)
+                    google.protobuf.text_format.Merge(f1.read(), req.config.p4info, allow_unknown_field=True)
                 except google.protobuf.text_format.ParseError:
                     logging.error("Error when parsing P4Info")
                     raise