Fix UB when HttpStatus code is not one in the enum.

PiperOrigin-RevId: 736244405

internal/network/http_status_code.cc

@@ -109,6 +109,8 @@ absl::string_view GetHttpReasonPhrase(HttpStatusCode code) {
       return "Gateway Timeout";
     case HttpStatusCode::kHttpVersionNotSupported:
       return "HTTP Version Not Supported";
+    default:
+      return "Unknown HTTP status code";
   }
 }
 

internal/network/http_status_code_test.cc

@@ -100,6 +100,8 @@ TEST(HttpStatusCode, TestReturnCorrectReasonPhrase) {
             "HTTP Version Not Supported");
   EXPECT_EQ(GetHttpReasonPhrase(HttpStatusCode::kHttpRequestUriTooLong),
             "Request-URI Too Long");
+  EXPECT_EQ(GetHttpReasonPhrase(static_cast<HttpStatusCode>(600)),
+           "Unknown HTTP status code");
 }
 
 }  // namespace