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/MockHWComposer.h b/services/surfaceflinger/CompositionEngine/tests/MockHWComposer.h
index 9971791..502a33f 100644
--- a/services/surfaceflinger/CompositionEngine/tests/MockHWComposer.h
+++ b/services/surfaceflinger/CompositionEngine/tests/MockHWComposer.h
@@ -19,8 +19,15 @@
 #include <compositionengine/Output.h>
 #include <gmock/gmock.h>
 
+// TODO(b/129481165): remove the #pragma below and fix conversion issues
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wconversion"
+
 #include "DisplayHardware/HWComposer.h"
 
+// TODO(b/129481165): remove the #pragma below and fix conversion issues
+#pragma clang diagnostic pop // ignored "-Wconversion"
+
 namespace android {
 namespace mock {