delete all example/android/app/gradle.properties files (#2208)
delete all example/android/app/gradle.properties files (#2208)


fluttercommunity/plus_plugins,fluttercommunity/plus_plugins,fluttercommunity/plus_plugins,fluttercommunity/plus_plugins,fluttercommunity/plus_plugins,fluttercommunity/plus_plugins,fluttercommunity/plus_plugins,fluttercommunity/plus_plugins,fluttercommunity/plus_plugins,fluttercommunity/plus_plugins,fluttercommunity/plus_plugins