feat: add defaultAutoResponsiveFormLayout feature flag (#21108)

The PR introduces a new feature flag, defaultAutoResponsiveFormLayout, which enables auto-responsive mode for all form layouts by default.

Part of vaadin/flow-components#7164

Author: vursen

flow-server/src/main/java/com/vaadin/experimental/FeatureFlags.java

@@ -109,6 +109,11 @@ public class FeatureFlags implements Serializable {
             "https://github.com/vaadin/flow-components/issues/6998", true,
             null);
 
+    public static final Feature DEFAULT_AUTO_RESPONSIVE_FORM_LAYOUT = new Feature(
+            "Form Layout auto-responsive mode enabled by default",
+            "defaultAutoResponsiveFormLayout",
+            "https://github.com/vaadin/platform/issues/7172", true, null);
+
     private List<Feature> features = new ArrayList<>();
 
     File propertiesFolder = null;
@@ -140,6 +145,7 @@ public FeatureFlags(Lookup lookup) {
         features.add(new Feature(REACT19));
         features.add(new Feature(ACCESSIBLE_DISABLED_BUTTONS));
         features.add(new Feature(LAYOUT_COMPONENT_IMPROVEMENTS));
+        features.add(new Feature(DEFAULT_AUTO_RESPONSIVE_FORM_LAYOUT));
         loadProperties();
     }