Fix -Wunused-variable compiler warning

Test: presubmit
Change-Id: I69a918d38492b91cb58223875fcb062bdd631a4c
diff --git a/services/surfaceflinger/tests/unittests/SurfaceFlinger_DisplayTransactionCommitTest.cpp b/services/surfaceflinger/tests/unittests/SurfaceFlinger_DisplayTransactionCommitTest.cpp
index 94d517a..b620830 100644
--- a/services/surfaceflinger/tests/unittests/SurfaceFlinger_DisplayTransactionCommitTest.cpp
+++ b/services/surfaceflinger/tests/unittests/SurfaceFlinger_DisplayTransactionCommitTest.cpp
@@ -110,7 +110,7 @@
     EXPECT_EQ(static_cast<bool>(Case::Display::PRIMARY), display.isPrimary());
 
     std::optional<DisplayDeviceState::Physical> expectedPhysical;
-    if (const auto connectionType = Case::Display::CONNECTION_TYPE::value) {
+    if (Case::Display::CONNECTION_TYPE::value) {
         const auto displayId = PhysicalDisplayId::tryCast(Case::Display::DISPLAY_ID::get());
         ASSERT_TRUE(displayId);
         const auto hwcDisplayId = Case::Display::HWC_DISPLAY_ID_OPT::value;