fix: panic due to potentially uncomparable wrapped fn in express_resolve (#2500)

Author: lucix-aws

.changelog/4160aee8b3204fc5bb030e0f5b068f5c.json

@@ -0,0 +1,8 @@
+{
+    "id": "4160aee8-b320-4fc5-bb03-0e0f5b068f5c",
+    "type": "bugfix",
+    "description": "Prevent potential panic caused by invalid comparison of credentials.",
+    "modules": [
+        "service/s3"
+    ]
+}

service/s3/express_resolve.go

@@ -24,14 +24,9 @@ func finalizeExpressCredentials(o *Options, c *Client) {
 }
 
 // Operation config finalizer: update the sigv4 credentials on the default
-// express provider if it changed to ensure different cache keys
+// express provider in case it changed to ensure different cache keys
 func finalizeOperationExpressCredentials(o *Options, c Client) {
-	p, ok := o.ExpressCredentials.(*defaultS3ExpressCredentialsProvider)
-	if !ok {
-		return
-	}
-
-	if c.options.Credentials != o.Credentials {
+	if p, ok := o.ExpressCredentials.(*defaultS3ExpressCredentialsProvider); ok {
 		o.ExpressCredentials = p.CloneWithBaseCredentials(o.Credentials)
 	}
 }