[sf] Use a unique sequence number when tracking layers in planner

Fixes caching issues with new frontend.

Test: presubmit
Bug: 238781169
Change-Id: I20a345283d07dbeea6e0d09e7acf42b2064e20e8
diff --git a/services/surfaceflinger/LayerFE.cpp b/services/surfaceflinger/LayerFE.cpp
index a0024d5..97c4145 100644
--- a/services/surfaceflinger/LayerFE.cpp
+++ b/services/surfaceflinger/LayerFE.cpp
@@ -345,7 +345,7 @@
 }
 
 int32_t LayerFE::getSequence() const {
-    return mSnapshot->sequence;
+    return static_cast<int32_t>(mSnapshot->uniqueSequence);
 }
 
 bool LayerFE::hasRoundedCorners() const {