[i273a] GUI: Change default color map (#273) ()

Merging branch 'i273a'  into 'main'.

See merge request !813

GUI/Model/Data/IntensityDataItem.cpp

@@ -38,7 +38,7 @@ ComboProperty gradientCombo()
            << "Spectrum"
            << "Jet"
            << "Hues";
-    result.setValue("Jet");
+    result.setValue("Thermal");
     return result;
 }