Connect/Transform connectorConfig.topics property cleanup

[willddy]

Currently, we connect support "topics", we use , to separate different topic. The new UI will send these as array for instead for better user experience.

We should convert this array to string with comma separator

{
    "description":"This is default description.",
    "connectorConfig":{
        "tasks.max":"1",
        "topics":["test_value","output_value"],
        "file.overwrite":true,
        "file.location":"/home/vagrant/df_data",
        "file.glob":"*.json"
    },
    "connectorType":"CONNECT_KAFKA_SOURCE_AVRO",
    "name":"test",
    "taskSeq":1
}

[willddy]

• convertTopicsFromArrayToString is added to do such convert in HelpFunc.cleanJsonConfig when we add connect/transform
• Use ConstantApp.PK_DF_TOPICS_ALIAS = "topics,topic.in"; to set which config name need to do such conversion

[willddy]

@SchubertZhu , you can test it.