SF: Introduce a configure stage

Decouple hotplug processing from commit of display transactions, as a
step toward per-display commit/composite. The configure stage will be
responsible for mode setting as well.

Bug: 241285876
Test: libsurfaceflinger_unittest
Change-Id: I72b7223760fa5896debb046f158845a0b4f4599a
diff --git a/services/surfaceflinger/tests/unittests/MessageQueueTest.cpp b/services/surfaceflinger/tests/unittests/MessageQueueTest.cpp
index f20b9f9..5e1042e 100644
--- a/services/surfaceflinger/tests/unittests/MessageQueueTest.cpp
+++ b/services/surfaceflinger/tests/unittests/MessageQueueTest.cpp
@@ -32,6 +32,7 @@
 using CallbackToken = scheduler::VSyncDispatch::CallbackToken;
 
 struct NoOpCompositor final : ICompositor {
+    void configure() override {}
     bool commit(TimePoint, VsyncId, TimePoint) override { return false; }
     void composite(TimePoint, VsyncId) override {}
     void sample() override {}