add no sign request to archives docs (#19464)

## Description 

small docs update so users don't need to supply aws creds

---

## Release notes

Check each box that your changes affect. If none of the boxes relate to
your changes, release notes aren't required.

For each box you select, include information after the relevant heading
that describes the impact of your changes that a user might notice and
any actions they must take to implement updates.

- [ ] Protocol: 
- [ ] Nodes (Validators and Full nodes): 
- [ ] Indexer: 
- [ ] JSON-RPC: 
- [ ] GraphQL: 
- [ ] CLI: 
- [ ] Rust SDK:
- [ ] REST API:

docs/content/guides/operator/archives.mdx

@@ -52,11 +52,9 @@ state-archive-read-config:
       # Use mysten-testnet-archives for testnet 
       # Use mysten-mainnet-archives for mainnet
       bucket: "mysten-<testnet|mainnet>-archives"
-      # Use your AWS account access key id
-      aws-access-key-id: "<AWS-ACCESS-KEY-ID>"
-      # Use your AWS account secret access key
-      aws-secret-access-key: "<AWS-SECRET-ACCESS-KEY>"
-      aws-region: "<AWS-REGION>"
+      # you can either provide your own aws credentials via "aws-secret-access-key" and
+      # "aws-access-key-id" or set no-sign-request: true
+      no-sign-request: true
       object-store-connection-limit: 20
     # How many objects to read ahead when catching up  
     concurrency: 5