cloud_storage: fix s3 request parameters

In `ListObjectsV2` for the `s3_client`, `prefix`, `delimiter`,
`start_after`, and `continuation-token` are all URI parameters,
not request headers.

src/v/cloud_storage_clients/s3_client.cc

@@ -203,12 +203,18 @@ request_creator::make_list_objects_v2_request(
     if (prefix.has_value()) {
         key = fmt::format("{}&prefix={}", key, (*prefix)().string());
     }
-    if (delimiter.has_value()) {
-        key = fmt::format("{}&delimiter={}", key, *delimiter);
+    if (start_after.has_value()) {
+        key = fmt::format("{}&start-after={}", key, *start_after);
     }
     if (max_keys.has_value()) {
         key = fmt::format("{}&max-keys={}", key, *max_keys);
     }
+    if (continuation_token.has_value()) {
+        key = fmt::format("{}&continuation-token={}", key, *continuation_token);
+    }
+    if (delimiter.has_value()) {
+        key = fmt::format("{}&delimiter={}", key, *delimiter);
+    }
     auto target = make_target(name, object_key{key});
     header.method(boost::beast::http::verb::get);
     header.target(target);
@@ -217,23 +223,6 @@ request_creator::make_list_objects_v2_request(
     header.insert(boost::beast::http::field::host, host);
     header.insert(boost::beast::http::field::content_length, "0");
 
-    if (prefix) {
-        header.insert(aws_header_names::prefix, (*prefix)().string());
-    }
-    if (start_after) {
-        header.insert(aws_header_names::start_after, (*start_after)().string());
-    }
-    if (continuation_token) {
-        header.insert(
-          aws_header_names::continuation_token,
-          {continuation_token->data(), continuation_token->size()});
-    }
-
-    if (delimiter) {
-        header.insert(
-          aws_header_names::delimiter, std::string(1, delimiter.value()));
-    }
-
     auto ec = _apply_credentials->add_auth(header);
     vlog(s3_log.trace, "ListObjectsV2:\n {}", header);
     if (ec) {