Condition to model in join: exclude predict target

[ea-rus]

Update of: #327 (mindsdb/mindsdb#5379)

If column is a model output (like in example below), don't use it as input to model. Keep it as filter

   SELECT *  FROM yt.comments c
    JOIN yt_sentiment_classifier AS m
    WHERE m.sentiment = 'positive';

[chandrevdw31]

works