[automerger skipped] DO NOT MERGE: Add a soong var that will be used to...

[automerger skipped] DO NOT MERGE: Add a soong var that will be used to enable/disable rust am: 09132f63 -s ours

am skip reason: subject contains skip directive

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/modules/DnsResolver/+/13894017

Change-Id: I589081bafed19553303c8cc6ead432a4d40641d9