Reset taskbarModePreference on tearDown()

This CL forcefully resets taskbarModePreference on tearDown() to ensure
the following tests are not affected by the changes made by
`testTaskbarPinningChangeInLockedTaskbarChange`.

Bug: 368322666
Flag: EXEMPT bug fix
Test: nexus_unit_test_multi_device_platform
Change-Id: I8bd8e8ca8b4b832ed17e86fbdfc9bda7bf9ab16e
diff --git a/tests/multivalentTests/src/com/android/launcher3/util/DisplayControllerTest.kt b/tests/multivalentTests/src/com/android/launcher3/util/DisplayControllerTest.kt
index d4e4bd2..cf71370 100644
--- a/tests/multivalentTests/src/com/android/launcher3/util/DisplayControllerTest.kt
+++ b/tests/multivalentTests/src/com/android/launcher3/util/DisplayControllerTest.kt
@@ -41,6 +41,7 @@
 import junit.framework.Assert.assertFalse
 import junit.framework.Assert.assertTrue
 import kotlin.math.min
+import org.junit.After
 import org.junit.Before
 import org.junit.Test
 import org.junit.runner.RunWith
@@ -137,6 +138,13 @@
         displayController.addChangeListener(displayInfoChangeListener)
     }
 
+    @After
+    fun tearDown() {
+        // We need to reset the taskbar mode preference override even if a test throws an exception.
+        // Otherwise, it may break the following tests' assumptions.
+        DisplayController.enableTaskbarModePreferenceForTests(false)
+    }
+
     @Test
     @UiThreadTest
     fun testRotation() {