chore: use type narrowing around nested object access

Author: mfontanini

client-vms/src/vm/builder.ts

@@ -196,10 +196,7 @@ export class VmClientBuilder {
       }
     }
 
-    if (
-      !leaderClusterInfo.publicKeys ||
-      !leaderClusterInfo.publicKeys.authentication
-    )
+    if (!leaderClusterInfo.publicKeys?.authentication)
       throw new Error("Leader public key not in cluster details");
 
     const user_id = UserId.from(tokenAuthManager.publicKey);
@@ -209,7 +206,7 @@ export class VmClientBuilder {
       .id(user_id)
       .signer(signer)
       .leader(leader.transport)
-      .leaderPublicKey(leaderClusterInfo.publicKeys?.authentication)
+      .leaderPublicKey(leaderClusterInfo.publicKeys.authentication)
       .build();
 
     const config = VmClientConfig.parse({