[pgsql tracing] PGSQL protocol parsing should correctly ignore unsupported messages

[sync-by-unito[bot]]

Existing code does not support all message types of PGSQL, because of lack of time.

The behavior, however, just errors out when encounter unrecognized message types. That is wrong. As certain unhandled message will cause the whole parsing pipeline restart, and causes cascading failures down the pipeline, like messing up the message stitching.

So the code should be changed to recognize the message but leave them unparsed, and correctly ignores the bytes in the message flow to go on to process other messages.

┆Issue is synchronized with this Jira Bug by Unito