Dump a copy of metadata file for full OTA

When building the full OTA file, write a copy of the metadata to the
dist dir. Then it will show up in the artifact of the build page for
users to parse.

Bug: 124783265
Test: make dist and check the output metadata
Change-Id: I2eb06bbf3cbb9f3653ca3352f3d601b09403d59d
diff --git a/core/main.mk b/core/main.mk
index 610ab28..3f916ae 100644
--- a/core/main.mk
+++ b/core/main.mk
@@ -1454,6 +1454,7 @@
   $(call dist-for-goals, droidcore, \
     $(INTERNAL_UPDATE_PACKAGE_TARGET) \
     $(INTERNAL_OTA_PACKAGE_TARGET) \
+    $(INTERNAL_OTA_METADATA) \
     $(INTERNAL_OTA_RETROFIT_DYNAMIC_PARTITIONS_PACKAGE_TARGET) \
     $(BUILT_OTATOOLS_PACKAGE) \
     $(SYMBOLS_ZIP) \