Remove validation cookie support code

src/test/csf/Validation.h

@@ -55,7 +55,6 @@ class Validation
     PeerID nodeID_{0};
     bool trusted_ = false;
     bool full_ = false;
-    std::uint64_t cookie_;
     boost::optional<std::uint32_t> loadFee_;
 
 public:
@@ -69,7 +68,6 @@ public:
         PeerKey key,
         PeerID nodeID,
         bool full,
-        std::uint64_t cookie,
         boost::optional<std::uint32_t> loadFee = boost::none)
         : ledgerID_{id}
         , seq_{seq}
@@ -78,7 +76,6 @@ public:
         , key_{key}
         , nodeID_{nodeID}
         , full_{full}
-        , cookie_{cookie}
         , loadFee_{loadFee}
     {
     }
@@ -147,12 +144,6 @@ public:
         return *this;
     }
 
-    std::uint64_t
-    cookie() const
-    {
-        return cookie_;
-    }
-
     auto
     asTie() const
     {