Move common gradle config into convention plugins.

image-editor/app/src/test/java/com/example/imageeditor/app/ExampleUnitTest.kt

@@ -1,9 +1,8 @@
 package com.example.imageeditor.app
 
+import org.junit.Assert.assertEquals
 import org.junit.Test
 
-import org.junit.Assert.*
-
 /**
  * Example local unit test, which will execute on the development machine (host).
  *
@@ -14,4 +13,4 @@ class ExampleUnitTest {
   fun addition_isCorrect() {
     assertEquals(4, 2 + 2)
   }
-}
+}