Issue title: Bubble up log errors into KSQL show commands
 Issue body: I had an Avro error that showed up in the KSQL log files.  

However, aside from the lack of stats in `EXPLAIN QUERY`, I couldn’t find indication in KSQL CLI that this Avro error had occurred. Can we bubble something up into `EXPLAIN QUERY` that counts number of exceptions, or gives any indication that something might be wrong?
 Comments: 
 Comment 0: +1 this is not a nice user experience, particularly for people new to KSQL (and maybe Kafka in general). 

If I CTAS/CSAS from `ksql>` I expect to see some kind of message that the resulting query died, at a very minimum. 

Better would be this, plus showing the state of the query (e.g.  `ABORTED` or whatever the term would be) in `DESCRIBE EXTENDED` as well as `EXPLAIN`. 

Even better would be a console warning if I try to select from an object into which the source query is dead.
{'source': 'GithubIssues', 'repo_name_with_owner': 'confluentinc/ksql', 'issue_id': 309572121, 'repo_stars': 5324.0}