Add block number to activated leaves and associated fixes (#2718)

* add number to `ActivatedLeavesUpdate`

* update subsystem util and overseer

* use new ActivatedLeaf everywhere

* sort view

* sorted and limited view in network bridge

* use live block hash only if it's newer

* grumples
11 jobs for master
in 24 minutes and 46 seconds, using 0 compute credits, and was queued for 2 seconds