V1.04: Update build.gradle

Execution failed for task ':pdfrx:mergeReleaseNativeLibs'.
> A failure occurred while executing com.android.build.gradle.internal.tasks.MergeNativeLibsTask$MergeNativeLibsTaskWorkAction
   > 2 files found with path 'lib/arm64-v8a/libpdfium.so' from inputs:
      - /jenkins/workspace/head_amos_mobile_exec/amos_mobile_exec/build/pdfrx/intermediates/merged_jni_libs/release/out/arm64-v8a/libpdfium.so
      - /jenkins/workspace/head_amos_mobile_exec/amos_mobile_exec/build/pdfrx/intermediates/cxx/RelWithDebInfo/6i5b2q3w/obj/arm64-v8a/libpdfium.so
     If you are using jniLibs and CMake IMPORTED targets, see
     https://developer.android.com/r/tools/jniLibs-vs-imported-targets