Minor changes in utils::Status (#9288)

* Minor changes in utils::Status

- << operator doesn't have to be friend
- simplify getErrorMessage to not use strlen internally

* Replace std::ostream to utils::io::ostream

libs/utils/src/Status.cpp

@@ -15,13 +15,11 @@
  */
 #include <utils/Status.h>
 
-namespace utils {
-std::string_view Status::getErrorMessage() const {
-    const char* ptr = mErrorMessage.c_str();
-    return (ptr != nullptr) ? ptr : "";
-}
+#include <utils/ostream.h>
 
-std::ostream& operator<<(std::ostream& os, const Status& status) {
+namespace utils {
+
+utils::io::ostream& operator<<(utils::io::ostream& os, const Status& status) {
     os << "Status: ";
     switch (status.getCode()) {
         case StatusCode::OK: os << "Ok";