[Bug] repaired not adhering placement ledger feature can not repair opened ledger

**BUG REPORT**

I also do a disaster recovery test, and try to use this feature to repair ledger. https://github.com/apache/bookkeeper/pull/3359

But it can not repair the ledger of pulsar "__change_event_" topic, because its ledger is opened status.

***Expected behavior***

Now my solution is also repair the opened ledger, and ensure not write the opened ledger by do not modify the topic metadata.

But I wonder if there have better way ?

By the way, now we can not repair not adhering RegionAware placement ledger. Can we add a config minNumRegionsPerWriteQuorum, just as minNumRacksPerWriteQuorum, to ensure quorum must be distributed in at least 3 regions ?