chore: hookup hare4 handler (#6391)

## Motivation

p2p server was not hooked up correctly, causing errors on stream handling.

hare4/hare.go

@@ -291,6 +291,7 @@ func (h *Hare) Coins() <-chan WeakCoinOutput {
 
 func (h *Hare) Start() {
 	h.pubsub.Register(h.config.ProtocolName, h.Handler, pubsub.WithValidatorInline(true))
+	h.eg.Go(func() error { return h.p2p.Run(h.ctx) })
 	current := h.nodeClock.CurrentLayer() + 1
 	enabled := max(current, h.config.EnableLayer, types.GetEffectiveGenesis()+1)
 	disabled := types.LayerID(math.MaxUint32)

hare4/hare_test.go

@@ -221,6 +221,7 @@ func (n *node) withPublisher() *node {
 
 func (n *node) withStreamRequester() *node {
 	n.mockStreamRequester = hmock.NewMockstreamRequester(n.ctrl)
+	n.mockStreamRequester.EXPECT().Run(gomock.Any()).Return(nil).AnyTimes()
 	return n
 }
 

hare4/interface.go

@@ -12,6 +12,7 @@ import (
 //go:generate mockgen -typed -package=mocks -destination=./mocks/mocks.go -source=./interface.go
 
 type streamRequester interface {
+	Run(ctx context.Context) error
 	StreamRequest(context.Context, p2p.Peer, []byte, server.StreamRequestCallback, ...string) error
 }