If rollback_index is specified use it in the dice chain of pVM

Ideally the subcomponents part of the payload node should have both
version and security_version, but this is not the case for now. Hence we
just override the security_version with the value of rollback_index.

Bug: 378681279
Test: atest MicrodroidTests
Change-Id: I3c4ecb0f7d725bd76347bdac1caa62b3c9106e06
diff --git a/guest/microdroid_manager/src/instance.rs b/guest/microdroid_manager/src/instance.rs
index d3a597a..a5f0d66 100644
--- a/guest/microdroid_manager/src/instance.rs
+++ b/guest/microdroid_manager/src/instance.rs
@@ -290,6 +290,7 @@
     pub cert_hash: Vec<u8>,
     pub package_name: String,
     pub version_code: u64,
+    pub rollback_index: Option<u32>,
 }
 
 impl ApkData {