connector: allow customization on the prefix of group.id for Kafka readers

[BugenZhao]

Currently we hardcode it to be consumer-. Users may want to customize it to be consumer_ or something else.

risingwave/src/connector/src/source/kafka/source/reader.rs

Lines 79 to 90 in e723f6a

	if config.get("group.id").is_none() {
	config.set(
	"group.id",
	format!(
	"consumer-{}",
	SystemTime::now()
	.duration_since(UNIX_EPOCH)
	.unwrap()
	.as_micros()
	),
	);
	}

Note that specifying the whole group id is not expected as described in #13223 (comment). So maybe we should remove consumer_group from properties to avoid confusion.

cc @shanicky @tabVersion

[tabVersion]

So maybe we should remove consumer_group from properties to avoid confusion.

We've removed the group.id from the dev doc to avoid unexpected behavior.

Users may want to customize it to be consumer_ or something else.

I am afraid of bringing up more confusion for normal users that we have to explain how RW uses the low-level API and how splits are distributed to different actors. group.id is required by the kafka client but we don't necessarily need it.

[github-actions]

This issue has been open for 60 days with no activity. Could you please update the status? Feel free to continue discussion or close as not planned.

[xxchan]

#17657