Move debug error message from failed pub to logger.printTrace (#118379)

* Move debug error message from failed pub to logger.printTrace

* Update test

packages/flutter_tools/lib/src/dart/pub.dart

@@ -475,10 +475,8 @@ class _DefaultPub implements Pub {
       buffer.writeln('command: "${pubCommand.join(' ')}"');
       buffer.write(_stringifyPubEnv(pubEnvironment));
       buffer.writeln('exit code: $code');
-      throwToolExit(
-        buffer.toString(),
-        exitCode: code,
-      );
+      _logger.printTrace(buffer.toString());
+      throwToolExit(null, exitCode: code);
     }
   }
 

packages/flutter_tools/test/general.shard/dart/pub_get_test.dart

@@ -555,9 +555,10 @@ exit code: 66
         project: FlutterProject.fromDirectoryTest(fileSystem.currentDirectory),
         context: PubContext.flutterTests,
       ),
-      throwsA(isA<ToolExit>().having((ToolExit error) => error.message, 'message', toolExitMessage)),
+      throwsA(isA<ToolExit>().having((ToolExit error) => error.message, 'message', null)),
     );
     expect(logger.statusText, isEmpty);
+    expect(logger.traceText, contains(toolExitMessage));
     expect(
       mockStdio.stdout.writes.map(utf8.decode),
       <String>[