Use Migrator Tool to Automatically Opt-in to newDsl in 3.50

Pre-reqs
The Flutter team has added support such that app and plugin developers can opt-in to newDsl. This is not done yet and is tracked by this: #180137

Use the migrator tool to set android.newDsl=true. We can set that to true as soon as we are done with work on our end. There should be no action required by developers. Developers will be unable to opt-out of built-in kotlin in AGP 10.