t/android_common: Fix lint errors for !! usages
The lint doesn't recommend us to use someVariable!!,
and we can use built-in Kotlin's requireNotNull and with
scope function to use variables without errors.
Signed-off-by: utzcoz <utzcoz@outlook.com>
Part-of: <https://gitlab.freedesktop.org/monado/monado/-/merge_requests/2382>