refactor(relayer): Defer origin chain limits computation (#1793)

If there are no deposits then it doesn't make sense to compute this.
Defer it in order to reduce log noise.

src/relayer/Relayer.ts

@@ -717,8 +717,6 @@ export class Relayer {
       .flat()
       .map(({ deposit }) => deposit);
 
-    this.fillLimits = this.computeFillLimits();
-
     this.logger.debug({
       at: "Relayer::checkForUnfilledDepositsAndFill",
       message: `${allUnfilledDeposits.length} unfilled deposits found.`,
@@ -727,6 +725,8 @@ export class Relayer {
       return txnReceipts;
     }
 
+    this.fillLimits = this.computeFillLimits();
+
     const lpFees = await this.batchComputeLpFees(allUnfilledDeposits);
     await sdkUtils.forEachAsync(Object.entries(unfilledDeposits), async ([chainId, _deposits]) => {
       if (_deposits.length === 0) {

test/Relayer.BasicFill.ts

@@ -503,7 +503,7 @@ describe("Relayer: Check for Unfilled Deposits and Fill", async function () {
       for (const receipts of Object.values(txnReceipts)) {
         expect((await receipts).length).to.equal(0);
       }
-      expect(spyLogIncludes(spy, -3, "due to insufficient deposit confirmations.")).to.be.true;
+      expect(spyLogIncludes(spy, -2, "due to insufficient deposit confirmations.")).to.be.true;
       expect(lastSpyLogIncludes(spy, "0 unfilled deposits found.")).to.be.true;
     });