[Bug] Handle Strings Properly in PostgresResultIteratorWithMetaData #101

PostgresResultIteratorWithMetaData has a bug on line 822 wherein Jackson's Object Mapper tries to deserialise a string but throws a JsonParsingException. The problem here is that we are passing the string without escaping the double quotes. This needs to be fixed.

Note: We need to check the column type and escape only if it is a text column. For other numeric cols, it shouldn't be escaped.