Skip SOLID_COLOR layers from SF Caching

Layers with SOLID_COLOR compostion type may cause fence leaks, and since these layers are not frequently used, skipping them should be ok.
Bug: 230073351
Test: manual, examine logs

Change-Id: I50c2488c4c5b891bf0415f1d4bd29a6e0c49be5b
diff --git a/services/surfaceflinger/CompositionEngine/src/OutputLayer.cpp b/services/surfaceflinger/CompositionEngine/src/OutputLayer.cpp
index 742af58..1bb9d0eb 100644
--- a/services/surfaceflinger/CompositionEngine/src/OutputLayer.cpp
+++ b/services/surfaceflinger/CompositionEngine/src/OutputLayer.cpp
@@ -377,6 +377,7 @@
     auto requestedCompositionType = outputIndependentState->compositionType;
 
     if (requestedCompositionType == Composition::SOLID_COLOR && state.overrideInfo.buffer) {
+        // this should never happen, as SOLID_COLOR is skipped from caching, b/230073351
         requestedCompositionType = Composition::DEVICE;
     }