group-store: make %migrate idempotent

pkg/landscape/app/group-store.hoon

@@ -245,7 +245,7 @@
 ++  poke-migrate
   ^-  (quip card _state)
   =^  cards-1=(list card)  wait
-    ~(migrate-start gladio bol)
+    (~(migrate-start gladio bol) wait)
   =/  cards-2=(list card)
     (turn ~(tap in wait) watch-init-migrate)
   =/  cards  (welp cards-1 cards-2)

pkg/landscape/lib/gladio.hoon

@@ -95,6 +95,7 @@
   |=  [=dude:gall =cage]
   [%pass /gladio %agent [our.bowl dude] %poke cage]
 ++  migrate-start
+  |=  wait=(set ship)
   ^-  (quip card (set ship))
   =+  network
   =+  associations
@@ -161,7 +162,7 @@
   ?.  split-ota
     :_  ~
     (welp setup (zing (turn ~(tap in (~(del in ships) our.bowl)) migrate-ship)))
-  [setup ships]
+  [setup (~(uni in ships) wait)]
 ::
 ++  migrate-ship
   |=  her=ship