Convert imageMutator to TransitionMutator

Replace android.imageMutator with a TransitionMutator

Test: diff out/soong/Android-<product>.mk
Bug: 319288033
Change-Id: Id6a50a2aacb32ecfadf7e45ada4956e85b55fef2
diff --git a/android/mutator.go b/android/mutator.go
index b81dd12..38fb857 100644
--- a/android/mutator.go
+++ b/android/mutator.go
@@ -149,7 +149,7 @@
 
 func registerArchMutator(ctx RegisterMutatorsContext) {
 	ctx.BottomUpBlueprint("os", osMutator).Parallel()
-	ctx.BottomUp("image", imageMutator).Parallel()
+	ctx.Transition("image", &imageTransitionMutator{})
 	ctx.BottomUpBlueprint("arch", archMutator).Parallel()
 }