Adds JNIExport to powersync_init so that it is exported in the Windows DLL#106

DominicGBauer merged 1 commit intopowersync-ja:mainpowersync-ja/powersync-kotlin:mainfrom

SalomonBrys:fix/windows-native-exportSalomonBrys/powersync-kotlin:fix/windows-native-exportCopy head branch name to clipboard