SF: Implement leader display promotion/demotion

Remove Scheduler::mRefreshRateSelector by using mLeaderDisplayId to look
up the leader's RefreshRateSelector. Replace setRefreshRateSelector with
setLeaderDisplay. Add logic to demote/promote the leader display (always
the primary display for now) when displays are added/changed/removed.

This fixes a regression where Scheduler::applyPolicy no longer respected
the active display after Ifa1bf23bc991fe60e67dba1cb31077e42fd5396e.

Bug: 255635821
Bug: 241286431
Test: Fold/unfold
Test: dumpsys SurfaceFlinger --scheduler
Change-Id: Ib1e8eacd2cdbf0d798ff7e8bb9c25607972104f5
diff --git a/services/surfaceflinger/Scheduler/RefreshRateSelector.h b/services/surfaceflinger/Scheduler/RefreshRateSelector.h
index 0e80817..65ee487 100644
--- a/services/surfaceflinger/Scheduler/RefreshRateSelector.h
+++ b/services/surfaceflinger/Scheduler/RefreshRateSelector.h
@@ -363,14 +363,16 @@
         }
     }
 
-    void resetIdleTimer(bool kernelOnly) {
-        if (!mIdleTimer) {
-            return;
+    void resetKernelIdleTimer() {
+        if (mIdleTimer && mConfig.kernelIdleTimerController) {
+            mIdleTimer->reset();
         }
-        if (kernelOnly && !mConfig.kernelIdleTimerController.has_value()) {
-            return;
+    }
+
+    void resetIdleTimer() {
+        if (mIdleTimer) {
+            mIdleTimer->reset();
         }
-        mIdleTimer->reset();
     }
 
     void dump(utils::Dumper&) const EXCLUDES(mLock);