ProjectExplorer: Add a convienience BuildStepList::firstStepWithId

For later use.

Change-Id: I696e3e03e1f8a82c25b29c9cf4b311360d83c12f
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

src/plugins/projectexplorer/buildsteplist.cpp

@@ -153,6 +153,11 @@ QList<BuildStep *> BuildStepList::steps() const
     return m_steps;
 }
 
+BuildStep *BuildStepList::firstStepWithId(Core::Id id) const
+{
+    return Utils::findOrDefault(m_steps, Utils::equal(&BuildStep::id, id));
+}
+
 void BuildStepList::insertStep(int position, BuildStep *step)
 {
     m_steps.insert(position, step);