fix(Visual): prevent fade mesh getting destroyed on disable

The movement of the mesh overlay seems to cause the component to get
disabled and then re-enabled causing the mesh to not be available
at some points, which means the fade doesn't work.

Instead of destroying the mesh when the component is disabled, it now
just disables the renderer component and makes the destroy mesh method
public so it can be manually destroyed.

Runtime/Visual/CameraColorOverlay.cs

@@ -228,6 +228,20 @@ public virtual void Blink()
             blinkRoutine = StartCoroutine(ResetBlink());
         }
 
+        /// <summary>
+        /// Destroys the fade mesh used in the Universal Render Pipeline. To recreate it, the component must be disabled then re-enabled.
+        /// </summary>
+        public virtual void DestroyFadeMesh()
+        {
+            if (urpFadeOverlay == null)
+            {
+                return;
+            }
+
+            urpFadeOverlay.transform.SetParent(null);
+            Destroy(urpFadeOverlay);
+        }
+
         protected virtual void OnEnable()
         {
             lastUsedCamera = null;
@@ -251,10 +265,13 @@ protected virtual void OnDisable()
             CancelBlinkRoutine();
             if (GraphicsSettings.renderPipelineAsset != null)
             {
+                if (fadeRenderer != null)
+                {
+                    fadeRenderer.enabled = false;
+                }
 #if UNITY_2019_1_OR_NEWER
                 RenderPipelineManager.beginCameraRendering -= UrpPreRender;
 #endif
-                DestroyFadeMesh();
             }
             else
             {
@@ -309,21 +326,6 @@ protected virtual void CreateFadeMesh()
             mesh.uv = uv;
         }
 
-        /// <summary>
-        /// Destroys the fade mesh used in the Universal Render Pipeline.
-        /// </summary>
-        protected virtual void DestroyFadeMesh()
-        {
-            if (urpFadeOverlay == null)
-            {
-                return;
-            }
-
-            urpFadeOverlay.transform.SetParent(null);
-            Destroy(urpFadeOverlay);
-
-        }
-
         /// <summary>
         /// Applies the given <see cref="Color"/> to the cameras via <see cref="CameraValidity"/> over the given duration.
         /// </summary>