treewide: replace deprecated http::reply::done()

src/v/cloud_io/tests/db_s3_imposter_fixture.cc

@@ -125,7 +125,7 @@ struct db_s3_imposter_fixture::handler : ss::httpd::handler_base {
             rep->set_status(ss::http::reply::status_type::bad_request);
         }
 
-        rep->done("xml");
+        rep->set_content_type("xml");
         co_return std::move(rep);
     }
 

src/v/http/tests/utils.cc

@@ -45,16 +45,15 @@ ss::future<std::unique_ptr<ss::http::reply>> flexible_function_handler::handle(
       .then([this](std::unique_ptr<ss::http::reply> rep) {
           if (
             _content_type_overrides.contains(rep->get_header("Content-Type"))) {
-              rep->done();
+              // content type already set via override; nothing to do
           } else if (_content_type == "xml") {
               // Because `application/xml` is not implemented as a mapping
               // in `http/mime_types.cc`, in order to construct a reply with
               // the `Content-Type` header set to `application/xml`, we
               // need to hard code a path here.
               rep->set_content_type("application/xml");
-              rep->done();
           } else {
-              rep->done(_content_type);
+              rep->set_content_type(_content_type);
           }
           return ss::make_ready_future<std::unique_ptr<ss::http::reply>>(
             std::move(rep));

src/v/redpanda/admin/server.cc

@@ -397,7 +397,6 @@ class rpc_handler : public ss::httpd::handler_base {
               std::current_exception());
             rep = serde::pb::rpc::internal_exception().handle(std::move(rep));
         }
-        rep->done();
         co_return rep;
     }