Configure up to 10 retries on agent failure (#2447)

Configure up to 10 retries on agnet failure

This PR configures the number of retries to 10 (as opposed to just
3, which is the default). This makes the agent more resilient
against watermark check failures, because the likelihood of hitting
only replicas that are behind gets lowered a lot and retrying takes time
too.

Addresses [this comment](#2446 (comment)).

src/frontend/src/flows/verifiableCredentials/vcIssuer.ts

@@ -25,6 +25,7 @@ export class VcIssuer {
     const agent = new HttpAgent({
       host: inferHost(),
       identity,
+      retryTimes: 10,
     });
 
     // Only fetch the root key when we're not in prod

src/frontend/src/utils/iiConnection.ts

@@ -379,6 +379,7 @@ export class Connection {
     const agent = new HttpAgent({
       identity: delegationIdentity,
       host: inferHost(),
+      retryTimes: 10,
     });
 
     // Only fetch the root key when we're not in prod