Revert "Move FlagManager to a common SF lib"

Revert submission 25261159-flagmanager_common

Reason for revert: build breakage: b/310935941

Reverted changes: /q/submissionid:25261159-flagmanager_common

Change-Id: I44795b34c4ef97b78c080d6421eb61a454675ddb
diff --git a/services/surfaceflinger/RefreshRateOverlay.cpp b/services/surfaceflinger/RefreshRateOverlay.cpp
index b960e33..6752a0b 100644
--- a/services/surfaceflinger/RefreshRateOverlay.cpp
+++ b/services/surfaceflinger/RefreshRateOverlay.cpp
@@ -16,8 +16,8 @@
 
 #include <algorithm>
 
-#include <common/FlagManager.h>
 #include "Client.h"
+#include "FlagManager.h"
 #include "Layer.h"
 #include "RefreshRateOverlay.h"