Revert "treewide: seastar module update and fix broken rest client"

This reverts commit 44d34663bc of PR
https://github.com/scylladb/scylladb/pull/25915.

Breaks articact tests on ARM, blocking us from building new images from
master.

ent/encryption/azure_host.cc

@@ -399,7 +399,8 @@ future<rjson::value> azure_host::impl::send_request(const sstring& host, unsigne
     client.target(path);
     client.method(httpd::operation_type::POST);
     client.add_header("Authorization", fmt::format("Bearer {}", token.token));
-    client.content("application/json", std::move(rjson::print(body)));
+    client.add_header("Content-Type", "application/json");
+    client.content(std::move(rjson::print(body)));
 
     azlog.trace("Sending request: {}", rest::redacted_request_type{ client.request(), filter });
 

ent/encryption/kms_host.cc

@@ -808,7 +808,7 @@ future<encryption::kms_host::impl::result_type> encryption::kms_host::impl::post
 
     client.add_header(AWS_AUTHORIZATION_HEADER, awsAuthString);
     client.target("/");
-    client.content(query.content_type, query.content);
+    client.content(query.content);
     client.method(httpclient::method_type::POST);
 
     kms_log.trace("Request: {}", client.request());

utils/azure/identity/service_principal_credentials.cc

@@ -170,7 +170,8 @@ future<sstring> service_principal_credentials::post(const sstring& body) {
     rest::httpclient client{_host, _port, std::move(creds), options};
     client.target(path);
     client.method(op);
-    client.content(mime_type, std::move(body));
+    client.add_header("Content-Type", mime_type);
+    client.content(std::move(body));
 
     if (az_creds_logger.is_enabled(log_level::trace)) {
         az_creds_logger.trace("[{}] Sending request: {}", *this, rest::redacted_request_type{ client.request(), filter });

utils/gcp/object_storage.cc

@@ -294,9 +294,13 @@ utils::gcp::storage::client::impl::send_with_retry(const std::string& path, cons
             req.add_header(k, v);
         }
 
+        if (!content_type.empty()) {
+            req.add_header(httpclient::CONTENT_TYPE_HEADER, content_type);
+        }
+
         std::visit(overloaded_functor {
-            [&](const std::string& s) { req.content(content_type, s); },
-            [&](const writer_and_size& ws) { req.content(content_type, ws.first, ws.second); }
+            [&](const std::string& s) { req.content(s); },
+            [&](const writer_and_size& ws) { req.content(ws.first, ws.second); }
         }, body);
 
         // GCP storage requires this even if content is empty

utils/rest/client.cc

@@ -39,12 +39,14 @@ void rest::request_wrapper::method(method_type type) {
     _req._method = httpd::type2str(type);
 }
 
-void rest::request_wrapper::content(std::string_view content_type, std::string_view content) {
-    _req.write_body(sstring(content_type), sstring(content));
+void rest::request_wrapper::content(std::string_view content) {
+    _req.content_length = content.size();
+    _req.content = sstring(content);
 }
 
-void rest::request_wrapper::content(std::string_view content_type, body_writer w, size_t len) {
-    _req.write_body(sstring(content_type), len, std::move(w));
+void rest::request_wrapper::content(body_writer w, size_t len) {
+    _req.content_length = len;
+    _req.body_writer = std::move(w);
 }
 
 void rest::request_wrapper::target(std::string_view s) {
@@ -217,7 +219,8 @@ future<> rest::send_request(std::string_view uri
         if (content_type.empty()) {
             content_type = "application/x-www-form-urlencoded";
         }
-        client.content(content_type, std::move(body));
+        client.content(std::move(body));
+        client.add_header(httpclient::CONTENT_TYPE_HEADER, content_type);
     }
 
     co_await client.send([&] (const http::reply& rep, std::string_view result) {

utils/rest/client.hh

@@ -41,8 +41,8 @@ public:
     using body_writer = decltype(std::declval<seastar::http::request>().body_writer);
 
     void method(method_type);
-    void content(std::string_view content_type, std::string_view);
-    void content(std::string_view content_type, body_writer, size_t);
+    void content(std::string_view);
+    void content(body_writer, size_t);
 
     void target(std::string_view);