Handle Redis protocol message separately

Closes #4504

Messages are not typical responses, so they need special handling. This
is different between RESP2 and 3, so this is the first instance where
the script layer needs to tell the difference.

testing/btest/scripts/base/protocols/redis/pubsub-resp3.zeek

@@ -0,0 +1,16 @@
+# @TEST-DOC: Test Zeek parsing pubsub commands in RESP3
+# @TEST-REQUIRES: have-spicy
+#
+# @TEST-EXEC: zeek -b -r $TRACES/redis/pubsub-resp3.pcap %INPUT >output
+# @TEST-EXEC: btest-diff output
+
+# Test pub/sub from Redis. This has two subscribers, one using a pattern. Then, the
+# messages that were published get printed to output.
+
+@load base/protocols/redis
+
+event Redis::server_push(c: connection, data: Redis::ReplyData)
+	{
+	# The first 2 are SUBSCRIBE replies, the other 3 are message and pmessage
+	print "Got published data!", data;
+	}

testing/btest/scripts/base/protocols/redis/pubsub.zeek

@@ -5,8 +5,12 @@
 # @TEST-EXEC: btest-diff output
 # @TEST-EXEC: btest-diff redis.log
 
-# Testing the example of pub sub in REDIS docs:
-# https://redis.io/docs/latest/develop/interact/pubsub/
-# These are just commands between two different clients, one PUBLISH and one SUBSCRIBE
+# Test pub/sub from Redis. This has two subscribers, one using a pattern. Then, the
+# messages that were published get printed to output.
 
 @load base/protocols/redis
+
+event Redis::server_push(c: connection, data: Redis::ReplyData)
+	{
+	print "Got published data!", data;
+	}