*: Enable allow overlapping blocks by default

[yeya24]

Is your proposal related to a problem?

After Prometheus dependency got upgraded to #5771, allow overlapping blocks is enabled by default for TSDBs. We have other components that are related to overlapping blocks checking.

1. Compactor. Compaction has a flag compact.enable-vertical-compaction to check whether to enable vertical compaction or not. We should make this enable by default, too.
2. Shipper. This one is more interesting. Now shipper disallows out of order block uploading and needs a flag shipper.allow-out-of-order-uploads to enable this. With vertical compaction enabled out of order upload shouldn't be an issue. But I'd love to hear more ideas whether we want to enable this or not.