Apply suggestions from code review

Author: SimonMarquis

core/designsystem/src/test/kotlin/com/google/samples/apps/nowinandroid/core/designsystem/ThemeTest.kt

@@ -45,7 +45,6 @@ import org.junit.Rule
 import org.junit.Test
 import org.junit.runner.RunWith
 import org.robolectric.RobolectricTestRunner
-import org.robolectric.annotation.Config
 import kotlin.test.assertEquals
 
 /**
@@ -57,7 +56,6 @@ import kotlin.test.assertEquals
  * design system.
  */
 @RunWith(RobolectricTestRunner::class)
-@Config(sdk = [33])
 class ThemeTest {
 
     @get:Rule