Add VM creation failure test for unsigned vendor image

Bug: 285855436
Test: atest MicrodroidTests#creationFailsWithUnsignedVendorPartition

Change-Id: I1a8ec9d08a12a05fabb67a776e47eeeb24cf23be
diff --git a/tests/testapk/Android.bp b/tests/testapk/Android.bp
index 6e8216f..6a30b1c 100644
--- a/tests/testapk/Android.bp
+++ b/tests/testapk/Android.bp
@@ -58,6 +58,7 @@
     data: [
         ":MicrodroidVmShareApp",
         ":test_microdroid_vendor_image",
+        ":test_microdroid_vendor_image_unsigned",
     ],
 }