Merge #1993: keychain_txout: apply_changeset restores spk cache before last revealed

6ddecc9 refactor(keychain_txout): `apply_changeset` restores spk cache before last revealed (valued mammal)

Pull request description:

  This patch improves readability and maintains logical consistency with the use of `spk_cache` throughout the `keychain_txout` module.

  While it might offer a performance benefit, the results are mostly comparable with the current benchmarks as far as I can tell. At least there's no indication that it would negatively impact performance.

  fixes #1975

  ### Changelog notice

  ### Checklists

  #### All Submissions:

  * [x] I followed the [contribution guidelines](https://github.com/bitcoindevkit/bdk/blob/master/CONTRIBUTING.md)

ACKs for top commit:
  LagginTimes:
    ACK 6ddecc9

Tree-SHA512: 4c11d049f94f332c88c63687d5147d25cc372d65b5f1d9d9c8784e1310e0f03e9aee479b684c255dbebb1510a7922331ad07cbcbdf47d534cf28ea8ee0e1be66

Author: ValuedMammal

crates/chain/src/indexer/keychain_txout.rs

@@ -938,16 +938,16 @@ impl<K: Clone + Ord + Debug> KeychainTxOutIndex<K> {
 
     /// Applies the `ChangeSet<K>` to the [`KeychainTxOutIndex<K>`]
     pub fn apply_changeset(&mut self, changeset: ChangeSet) {
-        for (did, index) in changeset.last_revealed {
-            let v = self.last_revealed.entry(did).or_default();
-            *v = index.max(*v);
-            self.replenish_inner_index_did(did, self.lookahead);
-        }
         if self.persist_spks {
             for (did, spks) in changeset.spk_cache {
                 self.spk_cache.entry(did).or_default().extend(spks);
             }
         }
+        for (did, index) in changeset.last_revealed {
+            let v = self.last_revealed.entry(did).or_default();
+            *v = index.max(*v);
+            self.replenish_inner_index_did(did, self.lookahead);
+        }
     }
 }