AbstractProcessStep: Use task tree for all subclasses

Introduce AbstractProcessStep::runRecipe() virtual method
with the default implementation.

Task-number: QTCREATORBUG-29168
Change-Id: Iac75f4c38f8ee91ad8ac9324bb27881a3722911f
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>
Reviewed-by: hjk <hjk@qt.io>

src/plugins/python/pysidebuildconfiguration.cpp

@@ -59,7 +59,7 @@ void PySideBuildStep::updatePySideProjectPath(const FilePath &pySideProjectPath)
     m_pysideProject.setValue(pySideProjectPath);
 }
 
-void PySideBuildStep::doRun()
+Tasking::GroupItem PySideBuildStep::runRecipe()
 {
     using namespace Tasking;
 
@@ -69,10 +69,9 @@ void PySideBuildStep::doRun()
         return SetupResult::Continue;
     };
 
-    runTaskTree({onGroupSetup(onSetup), defaultProcessTask()});
+    return Group { onGroupSetup(onSetup), defaultProcessTask() };
 }
 
-
 // PySideBuildConfiguration
 
 class PySideBuildConfiguration : public BuildConfiguration