SF: Extract VsyncConfig to its own header

...such that VsyncConfiguration does not depend on VsyncModulator.

Bug: 241285475
Bug: 241285191
Test: Build
Change-Id: I05b66a4ed2e6721b10ae90bdc6af2e49c22f2a59
diff --git a/services/surfaceflinger/Scheduler/Scheduler.h b/services/surfaceflinger/Scheduler/Scheduler.h
index 36280e3..a3e28b6 100644
--- a/services/surfaceflinger/Scheduler/Scheduler.h
+++ b/services/surfaceflinger/Scheduler/Scheduler.h
@@ -239,8 +239,8 @@
     // Retrieves the overridden refresh rate for a given uid.
     std::optional<Fps> getFrameRateOverride(uid_t) const EXCLUDES(mDisplayLock);
 
-    nsecs_t getLeaderVsyncPeriod() const EXCLUDES(mDisplayLock) {
-        return leaderSelectorPtr()->getActiveMode().fps.getPeriodNsecs();
+    Period getLeaderVsyncPeriod() const EXCLUDES(mDisplayLock) {
+        return leaderSelectorPtr()->getActiveMode().fps.getPeriod();
     }
 
     // Returns the framerate of the layer with the given sequence ID