Add missing obfuscation configuration

This PR should fix a reported crash: ``` E /Users/nabil.hachicha/Dev/realm/release/realm-java/realm/realm-library/src/main/cpp/jni_util/java_method.cpp:33: [realm-core-13.26.0] Assertion failed: m_method_id != nullptr with (method_name, signature) = ["onChange", "(B)V"] <backtrace not supported on this platform> !!! IMPORTANT: Please report this at https://github.com/realm/realm-core/issues/new/choose ``` Originating from [HELP-58718](https://jira.mongodb.org/browse/HELP-58718)