Switch to JDK 18 + newer command-line `sdkmanager`

[karlhorky]

The newer sdkmanager from the Command-Line Tools package now supports JDK versions newer than 8: https://stackoverflow.com/a/65782803/1268612

Would be good to switch to the new JDK 18 and the new command-line sdkmanager.

There's an example here that may be helpful in getting this set up:

https://github.com/karlhorky/android-rs-examples/blob/2eac6325a61980657d1952fe430619aaf1776c01/hello-world-no-studio/download.sh

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Related: Also opened this over here: edvinasbartkus/react-native-detox-github-actions#22