Merge bitcoindevkit/bdk#1385: Fix last seen unconfirmed

a2a64ffb6e fix(electrum)!: Remove `seen_at` param from `into_tx_graph` (valued mammal)
37fca35dde feat(tx_graph): Add method update_last_seen_unconfirmed (valued mammal)

Pull request description:

  A method `update_last_seen_unconfirmed` is added for `TxGraph` that allows inserting a `seen_at` time for all unanchored transactions.

  fixes #1336

  ### Changelog notice

  Changed:
  - Methods `into_tx_graph` and `into_confirmation_time_tx_graph`for `RelevantTxids` are changed to no longer accept a `seen_at` parameter.

  Added:
  - Added method `update_last_seen_unconfirmed` for `TxGraph`.

  ### Checklists

  #### All Submissions:

  * [x] I've signed all my commits
  * [x] I followed the [contribution guidelines](https://github.com/bitcoindevkit/bdk/blob/master/CONTRIBUTING.md)
  * [x] I ran `cargo fmt` and `cargo clippy` before committing

ACKs for top commit:
  evanlinjin:
    ACK a2a64ffb6e

Tree-SHA512: 9011e63314b0e3ffcd50dbf5024f82b365bab1cc834c0455d7410b682338339ed5284caa721ffc267c65fa26d35ff6ee86cde6052e82a6a79768547fbb7a45eb

crates/chain/tests/test_tx_graph.rs

@@ -1058,6 +1058,34 @@ fn test_changeset_last_seen_append() {
     }
 }
 
+#[test]
+fn update_last_seen_unconfirmed() {
+    let mut graph = TxGraph::<()>::default();
+    let tx = new_tx(0);
+    let txid = tx.txid();
+
+    // insert a new tx
+    // initially we have a last_seen of 0, and no anchors
+    let _ = graph.insert_tx(tx);
+    let tx = graph.full_txs().next().unwrap();
+    assert_eq!(tx.last_seen_unconfirmed, 0);
+    assert!(tx.anchors.is_empty());
+
+    // higher timestamp should update last seen
+    let changeset = graph.update_last_seen_unconfirmed(2);
+    assert_eq!(changeset.last_seen.get(&txid).unwrap(), &2);
+
+    // lower timestamp has no effect
+    let changeset = graph.update_last_seen_unconfirmed(1);
+    assert!(changeset.last_seen.is_empty());
+
+    // once anchored, last seen is not updated
+    let _ = graph.insert_anchor(txid, ());
+    let changeset = graph.update_last_seen_unconfirmed(4);
+    assert!(changeset.is_empty());
+    assert_eq!(graph.full_txs().next().unwrap().last_seen_unconfirmed, 2);
+}
+
 #[test]
 fn test_missing_blocks() {
     /// An anchor implementation for testing, made up of `(the_anchor_block, random_data)`.