improve(relayer): Test lowered ethers pollingInterval (#1788)

The current ethers polling interval is 4 seconds. In case of waiting on
transaction confirmation, this probably imposes unnecessary delays in
the fast relayer when it has many fills to make.

This is done for test purposes to see whether relayer fill times improve
as a result. Subject to the results, this should be upstreamed to the 
SDK and made configurable, such that the fast relayer can opt-in to a
lower pollingInterval, and that it can tune the interval per chain.

src/utils/ProviderUtils.ts

@@ -341,6 +341,19 @@ export class RetryProvider extends ethers.providers.StaticJsonRpcProvider {
           ...inputs
         )
     );
+
+    // This is added for interim testing to see whether relayer fill performance improves.
+    // @todo: Upstream this to the SDK where the relayer's implementation will be relocated.
+    this.providers.forEach((provider) => {
+      const url = getOriginFromURL(provider.connection.url);
+      const { pollingInterval } = provider;
+      provider.pollingInterval = 1000;
+      logger?.debug({
+        at: "RetryProvider",
+        message: `Dropped ${url} pollingInterval ${pollingInterval} -> ${provider.pollingInterval}.`,
+      });
+    });
+
     if (this.nodeQuorumThreshold < 1 || !Number.isInteger(this.nodeQuorumThreshold)) {
       throw new Error(
         `nodeQuorum,Threshold cannot be < 1 and must be an integer. Currently set to ${this.nodeQuorumThreshold}`