SF: Define mock::SurfaceInterceptor

Test: Builds
Bug: 74827900
Change-Id: I0051c41a55a8213627add5c1b1f80e7864fb0a9e
(cherry picked from commit e98c417072ee0f18d3ff5ca24d4205788a55c87b)
diff --git a/services/surfaceflinger/tests/unittests/Android.bp b/services/surfaceflinger/tests/unittests/Android.bp
index aa88cb1..8473a55 100644
--- a/services/surfaceflinger/tests/unittests/Android.bp
+++ b/services/surfaceflinger/tests/unittests/Android.bp
@@ -26,6 +26,7 @@
         "MockGraphicBufferProducer.cpp",
         "MockMessageQueue.cpp",
         "MockRenderEngine.cpp",
+        "MockSurfaceInterceptor.cpp",
     ],
     static_libs: [
         "libgmock",