Android: add namespace to support AGP 8

[fu89-team]

Lib is not usable with Gradle 8 (Android), just add namespace to build.gradle.
Thanks.

[alberto-cappellina]

hi @fu89-team, my pullrequest should fix your issue #46

[OliverNarramore]

Yes please

[ufukhawk]

https://pub.dev/packages/safe_device @OliverNarramore