CMakeProjectManager: Remove margins around CMakeBuildStep widget

Change-Id: I9b2a1a615f987c3dff9b5fcb29b0a10c5417f752
Reviewed-by: Cristian Adam <cristian.adam@qt.io>
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>

src/plugins/cmakeprojectmanager/cmakebuildstep.cpp

@@ -481,7 +481,7 @@ QWidget *CMakeBuildStep::createConfigWidget()
         builder.addRow(m_useiOSAutomaticProvisioningUpdates);
 
     builder.addRow({new QLabel(tr("Targets:")), frame});
-    auto widget = builder.emerge();
+    auto widget = builder.emerge(Layouting::WithoutMargins);
 
     updateDetails();