Fixed crash and asserts when heightfield is used without Terrain World

Signed-off-by: Sergey Pereslavtsev <pereslav@amazon.com>

Gems/PhysX/Code/Editor/DebugDraw.cpp

@@ -694,7 +694,12 @@ namespace PhysX
             const float minYBounds = -(numRows * heightfieldShapeConfig.GetGridResolution().GetY()) / 2.0f;
 
             auto heights = heightfieldShapeConfig.GetSamples();
-            
+
+            if (heights.empty())
+            {
+                return;
+            }
+
             for (int xIndex = 0; xIndex < numColumns - 1; xIndex++)
             {
                 for (int yIndex = 0; yIndex < numRows - 1; yIndex++)

Gems/PhysX/Code/Source/EditorHeightfieldColliderComponent.cpp

@@ -211,7 +211,12 @@ namespace PhysX
     {
         ClearHeightfield();
         InitHeightfieldShapeConfiguration();
-        InitStaticRigidBody();
+
+        if (!m_shapeConfig->GetSamples().empty())
+        {
+            InitStaticRigidBody();
+        }
+
         Physics::ColliderComponentEventBus::Event(GetEntityId(), &Physics::ColliderComponentEvents::OnColliderChanged);
     }
 

Gems/PhysX/Code/Source/HeightfieldColliderComponent.cpp

@@ -150,7 +150,13 @@ namespace PhysX
     {
         ClearHeightfield();
         InitHeightfieldShapeConfiguration();
-        InitStaticRigidBody();
+
+        Physics::HeightfieldShapeConfiguration& configuration = static_cast<Physics::HeightfieldShapeConfiguration&>(*m_shapeConfig.second);
+        if (!configuration.GetSamples().empty())
+        {
+            InitStaticRigidBody();
+        }
+
         Physics::ColliderComponentEventBus::Event(GetEntityId(), &Physics::ColliderComponentEvents::OnColliderChanged);
     }