feat(txpool) modify txpool guard to be for pipeline syncs only (#4075)

Co-authored-by: Matthias Seitz <matthias.seitz@outlook.de>

crates/net/network-api/src/lib.rs

@@ -49,6 +49,9 @@ pub trait NetworkInfo: Send + Sync {
 
     /// Returns `true` if the network is undergoing sync.
     fn is_syncing(&self) -> bool;
+
+    /// Returns `true` when the node is undergoing the very first Pipeline sync.
+    fn is_initially_syncing(&self) -> bool;
 }
 
 /// Provides general purpose information about Peers in the network.

crates/net/network-api/src/noop.rs

@@ -45,6 +45,10 @@ impl NetworkInfo for NoopNetwork {
     fn is_syncing(&self) -> bool {
         false
     }
+
+    fn is_initially_syncing(&self) -> bool {
+        false
+    }
 }
 
 impl PeersInfo for NoopNetwork {