Hide debug exposure entry when no related debug mode is enabled.

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Debug/DebugDisplay.cs

                 });
             }
 
-            list.Add(new DebugUI.FloatField { displayName = "Debug Exposure", getter = () => lightingDebugSettings.debugExposure, setter = value => lightingDebugSettings.debugExposure = value });
+            if (DebugNeedsExposure())
+                list.Add(new DebugUI.FloatField { displayName = "Debug Exposure", getter = () => lightingDebugSettings.debugExposure, setter = value => lightingDebugSettings.debugExposure = value });
 
             m_DebugLightingItems = list.ToArray();
             var panel = DebugManager.instance.GetPanel(k_PanelLighting, true);