Cleaned up sky editor setup for common settings.

com.unity.render-pipelines.high-definition/HDRP/Editor/Sky/HDRISky/HDRISkyEditor.cs

         {
             base.OnEnable();
 
+            // HDRI sky does not have control over sun display.
+            m_CommonUIElementsMask = 0xFFFFFFFF & ~(uint)(SkySettingsUIElement.IncludeSunInBaking);
+
             var o = new PropertyFetcher<HDRISky>(serializedObject);
             m_hdriSky = Unpack(o.Find(x => x.hdriSky));
         }
             PropertyField(m_hdriSky);
 
             EditorGUILayout.Space();
-
-            uint uiElements = 0xFFFFFFFF;
-            uiElements &= ~(uint)(SkySettingsUIElement.IncludeSunInBaking);
-            base.CommonSkySettingsGUI(uiElements);
+            base.CommonSkySettingsGUI();
         }
     }
 }

com.unity.render-pipelines.high-definition/HDRP/Editor/Sky/ProceduralSky/ProceduralSkyEditor.cs

         {
             base.OnEnable();
 
+            // Procedural sky orientation depends on the sun direction
+            m_CommonUIElementsMask = 0xFFFFFFFF & ~(uint)(SkySettingsUIElement.Rotation);
+
             var o = new PropertyFetcher<ProceduralSky>(serializedObject);
 
             m_SunSize = Unpack(o.Find(x => x.sunSize));
 
             EditorGUILayout.Space();
 
-            uint uiElements = 0xFFFFFFFF;
-            uiElements &= ~(uint)(SkySettingsUIElement.Rotation);
-            base.CommonSkySettingsGUI(uiElements);
+            base.CommonSkySettingsGUI();
         }
     }
 }

com.unity.render-pipelines.high-definition/HDRP/Editor/Sky/SkySettingsEditor.cs

         SerializedDataParameter m_EnvUpdatePeriod;
         SerializedDataParameter m_IncludeSunInBaking;
 
+        protected uint m_CommonUIElementsMask = 0xFFFFFFFF;
+
         public override void OnEnable()
         {
             var o = new PropertyFetcher<SkySettings>(serializedObject);
 
         }
 
-        protected void CommonSkySettingsGUI(uint uiElementMask = 0xFFFFFFFF)
+        protected void CommonSkySettingsGUI()
-            if ((uiElementMask & (uint)SkySettingsUIElement.Exposure) != 0)
+            if ((m_CommonUIElementsMask & (uint)SkySettingsUIElement.Exposure) != 0)
-            if ((uiElementMask & (uint)SkySettingsUIElement.Multiplier) != 0)
+            if ((m_CommonUIElementsMask & (uint)SkySettingsUIElement.Multiplier) != 0)
-            if ((uiElementMask & (uint)SkySettingsUIElement.Rotation) != 0)
+            if ((m_CommonUIElementsMask & (uint)SkySettingsUIElement.Rotation) != 0)
-            if ((uiElementMask & (uint)SkySettingsUIElement.UpdateMode) != 0)
+            if ((m_CommonUIElementsMask & (uint)SkySettingsUIElement.UpdateMode) != 0)
             {
                 PropertyField(m_EnvUpdateMode);
                 if (!m_EnvUpdateMode.value.hasMultipleDifferentValues && m_EnvUpdateMode.value.intValue == (int)EnvironementUpdateMode.Realtime)
                     EditorGUI.indentLevel--;
                 }
             }
-            if ((uiElementMask & (uint)SkySettingsUIElement.IncludeSunInBaking) != 0)
+            if ((m_CommonUIElementsMask & (uint)SkySettingsUIElement.IncludeSunInBaking) != 0)
                 PropertyField(m_IncludeSunInBaking);
         }
     }