Fix mjcPhysics island flag default.

PiperOrigin-RevId: 822088739
Change-Id: If3a87976dd319502160fd886a1823c12d72bebf1

include/mujoco/experimental/usd/mjcPhysics/sceneAPI.h

@@ -1343,7 +1343,7 @@ class MjcPhysicsSceneAPI : public UsdAPISchemaBase {
   ///
   /// | ||
   /// | -- | -- |
-  /// | Declaration | `uniform bool mjc:flag:island = 0` |
+  /// | Declaration | `uniform bool mjc:flag:island = 1` |
   /// | C++ Type | bool |
   /// | \ref Usd_Datatypes "Usd Type" | SdfValueTypeNames->Bool |
   /// | \ref SdfVariability "Variability" | SdfVariabilityUniform |

src/experimental/usd/mjcPhysics/generatedSchema.usda

@@ -126,7 +126,7 @@ class "MjcSceneAPI" (
         displayName = "Discrete-Time Inverse Dynamics Toggle"
         doc = "Enables discrete-time inverse dynamics with mj_inverse for integrators other than RK4."
     )
-    uniform bool mjc:flag:island = 0 (
+    uniform bool mjc:flag:island = 1 (
         displayName = "Constraint Island Discovery Toggle"
         doc = "Enables the discovery of constraint islands."
     )

src/experimental/usd/mjcPhysics/schema.usda

@@ -501,7 +501,7 @@ class "MjcSceneAPI"
         doc = """Enables multiple-contact collision detection for geom pairs using a general-purpose convex-convex collider."""
     )
 
-    uniform bool mjc:flag:island = False (
+    uniform bool mjc:flag:island = True (
         customData = {
             string apiName = "IslandFlag"
         }

test/experimental/usd/plugins/mjcf/mjcf_file_format_test.cc

@@ -1052,6 +1052,7 @@ TEST_F(MjcfSdfFileFormatPluginTest, TestPhysicsScenePrimDisableFlags) {
           nativeccd="disable"
           eulerdamp="disable"
           autoreset="disable"
+          island="disable"
         />
       </option>
     </mujoco>
@@ -1076,6 +1077,7 @@ TEST_F(MjcfSdfFileFormatPluginTest, TestPhysicsScenePrimDisableFlags) {
       MjcPhysicsTokens->mjcFlagNativeccd,
       MjcPhysicsTokens->mjcFlagEulerdamp,
       MjcPhysicsTokens->mjcFlagAutoreset,
+      MjcPhysicsTokens->mjcFlagIsland,
   };
   for (const auto& flag : kFlags) {
     ExpectAttributeEqual(stage, kPhysicsScenePrimPath.AppendProperty(flag),
@@ -1093,7 +1095,6 @@ TEST_F(MjcfSdfFileFormatPluginTest, TestPhysicsScenePrimEnableFlags) {
           fwdinv="enable"
           invdiscrete="enable"
           multiccd="enable"
-          island="enable"
         />
       </option>
     </mujoco>
@@ -1106,7 +1107,6 @@ TEST_F(MjcfSdfFileFormatPluginTest, TestPhysicsScenePrimEnableFlags) {
       MjcPhysicsTokens->mjcFlagFwdinv,
       MjcPhysicsTokens->mjcFlagInvdiscrete,
       MjcPhysicsTokens->mjcFlagMulticcd,
-      MjcPhysicsTokens->mjcFlagIsland,
   };
   // clang-format on
   for (const auto& flag : kFlags) {