validator-discovery: don't remove multiaddr of requested `PeerId`s (#4036)

* validator-discovery: remove from peer set before inserting

* bump spec versions

* rework into a companion

* fmt

* fix

* fix

* one more time

* one more try

* one more try

* Revert "one more try"

This reverts commit ab6568d3b828a33dc06f5650037597fc88dd06b1.

* one more try

* one more try

* Revert "one more try"

This reverts commit 8d7369f7b78633bd1b1c5ba3e0f2a0544bdd77a5.

* fix a warning

* fix another warn

* correct log

* fix compilation

* ffs

* less cloning

* Apply suggestions from code review

Co-authored-by: Pierre Krieger <[email protected]>

* add comments and a small refactoring

* use set_reserved_peers

* cargo update -p sp-io

* rename added to num_peers

* update Substrate

Co-authored-by: Pierre Krieger <[email protected]>
Co-authored-by: parity-processbot <>