opt-in to MTE async mode

[cameronaaron]

currently only benefits GrapheneOS users on Pixel 8 and 9 who don't turn on MTE for all apps or Molly manually. hopefully will be extended to all Pixel users and then more devices

[amanharwara]

could you add more context on what this does?

[cameronaaron]

This change improves the app’s ability to catch memory safety bugs on devices that support ARM’s Memory Tagging Extension, with minimal performance impact. It’s a proactive step toward more robust and secure code, especially important for a widely-used app it will also allow the app to take advantage of the mem tagging in Android 16