chore: Reduced spam logging in archiver (AztecProtocol#3671)

This PR reduces the redundant logging in the archiver.

# Checklist:
Remove the checklist to signal you've completed it. Enable auto-merge if
the PR is ready to merge.
- [ ] If the pull request requires a cryptography review (e.g.
cryptographic algorithm implementations) I have added the 'crypto' tag.
- [ ] I have reviewed my diff in github, line by line and removed
unexpected formatting changes, testing logs, or commented-out code.
- [ ] Every change is related to the PR description.
- [ ] I have
[linked](https://docs.github.com/en/issues/tracking-your-work-with-issues/linking-a-pull-request-to-an-issue)
this pull request to relevant issues (if any exist).

yarn-project/archiver/src/archiver/archiver.ts

@@ -197,20 +197,25 @@ export class Archiver implements L2BlockSource, L2LogsSource, ContractDataSource
 
     // TODO (#717): optimize this - there could be messages in confirmed that are also in pending.
     // Or messages in pending that are also cancelled in the same block. No need to modify storage for them.
-    // Store l1 to l2 messages
-    this.log('Adding pending l1 to l2 messages to store');
-    await this.store.addPendingL1ToL2Messages(retrievedPendingL1ToL2Messages.retrievedData);
-    // remove cancelled messages from the pending message store:
-    this.log('Removing pending l1 to l2 messages from store where messages were cancelled');
-    await this.store.cancelPendingL1ToL2Messages(retrievedCancelledL1ToL2Messages.retrievedData);
+
+    if (retrievedPendingL1ToL2Messages.retrievedData.length) {
+      // Store l1 to l2 messages
+      this.log(`Adding ${retrievedPendingL1ToL2Messages.retrievedData.length} pending l1 to l2 messages to store`);
+      await this.store.addPendingL1ToL2Messages(retrievedPendingL1ToL2Messages.retrievedData);
+    }
+
+    if (retrievedCancelledL1ToL2Messages.retrievedData.length) {
+      // remove cancelled messages from the pending message store:
+      this.log(
+        `Removing ${retrievedCancelledL1ToL2Messages.retrievedData.length} pending l1 to l2 messages from store where messages were cancelled`,
+      );
+      await this.store.cancelPendingL1ToL2Messages(retrievedCancelledL1ToL2Messages.retrievedData);
+    }
 
     // ********** Events that are processed per block **********
 
     // Read all data from chain and then write to our stores at the end
     const nextExpectedL2BlockNum = BigInt((await this.store.getBlockNumber()) + 1);
-    this.log(
-      `Retrieving chain state from L1 block: ${this.nextL2BlockFromL1Block}, next expected l2 block number: ${nextExpectedL2BlockNum}`,
-    );
     const retrievedBlocks = await retrieveBlocks(
       this.publicClient,
       this.rollupAddress,