Make BuildManifest.apk available in CompOS

Bug: 206869687
Test: See /mnt/extra-apk/0/assets/build_manifest in the VM
Change-Id: Ieb687804a5d8d9df9ec8ab565b006d53e6ad6363
diff --git a/compos/apk/assets/vm_config.json b/compos/apk/assets/vm_config.json
index 0e97228..260332e 100644
--- a/compos/apk/assets/vm_config.json
+++ b/compos/apk/assets/vm_config.json
@@ -10,6 +10,11 @@
       "--log_to_stderr"
     ]
   },
+  "extra_apks": [
+    {
+      "path": "/system/etc/security/fsverity/BuildManifest.apk"
+    }
+  ],
   "apexes": [
     {
       "name": "com.android.art"