TaskTree: Get rid of unneeded done handlers' arguments

Task-number: QTCREATORBUG-29834
Change-Id: I236dec27a292a1b006b7001d01ce620960380de9
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>
Reviewed-by: Marcus Tillmanns <marcus.tillmanns@qt.io>

src/plugins/cmakeprojectmanager/cmakebuildstep.cpp

@@ -365,7 +365,7 @@ GroupItem CMakeBuildStep::runRecipe()
         parseTarget = target();
         return SetupResult::Continue;
     };
-    const auto onParserError = [this](const QPointer<Target> &) {
+    const auto onParserError = [this] {
         emit addOutput(Tr::tr("Project did not parse successfully, cannot build."),
                        OutputFormat::ErrorMessage);
     };