Support incremental OTA in ota_extractor

Test: Run ota_extractor on an incremental OTA
Bug: 228326856

Change-Id: I8adcbb923a5ad53f35d6eddb9b29afedbc46b041
diff --git a/payload_consumer/install_plan.h b/payload_consumer/install_plan.h
index 0278ea5..883aa60 100644
--- a/payload_consumer/install_plan.h
+++ b/payload_consumer/install_plan.h
@@ -156,6 +156,8 @@
     uint64_t fec_offset{0};
     uint64_t fec_size{0};
     uint32_t fec_roots{0};
+
+    bool ParseVerityConfig(const PartitionUpdate&);
   };
   std::vector<Partition> partitions;