fix: release build crash with NoSuchMethodError for getNavInfoLiveData

[jokerttu]

Fixes release build crash with NoSuchMethodError for getNavInfoLiveData

Release builds crash with NoSuchMethodError: No static method getNavInfoLiveData() when using Android Auto. R8 minification was stripping NavInfoReceivingService.getNavInfoLiveData() because:

• The library had minifyEnabled true (libraries shouldn't minify themselves)
• No ProGuard keep rules existed for runtime-accessed methods

This PR removes minifyEnabled from library build (apps handle minification) and add consumer-rules.pro with keep rules for NavInfoReceivingService that automatically apply to consuming apps

Fixes #534

Pre-launch Checklist

• I read the Contributor Guide and followed the process outlined there for submitting PRs.
• I signed the CLA.
• I listed at least one issue that this PR fixes in the description above.
• I updated/added relevant documentation
• I added new tests to check the change I am making
• All existing and new tests are passing.

[TimoPieti]

LGTM