CE: Reduce scope of where -Wconversion is disabled

The local conversion warning have been addressed, and the only remaining
conversion warnings are in some of the header files that are included,
directly or indirectly.

Test: Builds
Bug: 129481165
Change-Id: If6b7b9055b17ef67872bb5e34a0ef090b1e1a768
diff --git a/services/surfaceflinger/CompositionEngine/tests/MockHWC2.h b/services/surfaceflinger/CompositionEngine/tests/MockHWC2.h
index 7fd6541..a51cc67 100644
--- a/services/surfaceflinger/CompositionEngine/tests/MockHWC2.h
+++ b/services/surfaceflinger/CompositionEngine/tests/MockHWC2.h
@@ -20,13 +20,21 @@
 #include <ui/Fence.h>
 #include <ui/FloatRect.h>
 #include <ui/GraphicBuffer.h>
-#include <ui/GraphicTypes.h>
+
 #include <ui/Rect.h>
 #include <ui/Region.h>
 #include <ui/Transform.h>
 
+// TODO(b/129481165): remove the #pragma below and fix conversion issues
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wconversion"
+
+#include <ui/GraphicTypes.h>
 #include "DisplayHardware/HWC2.h"
 
+// TODO(b/129481165): remove the #pragma below and fix conversion issues
+#pragma clang diagnostic pop // ignored "-Wconversion"
+
 namespace HWC2 {
 namespace mock {