Updating user agent formatting

[Chriztiaan]

For context, the current user agent strings are not parsed successfully and end up as "unknown" on the current and last 30 days connected device charts in the new dashboard.

Documented examples:

powersync-dart/1.6.4 Dart/3.4.2 linux
powersync-dart/1.6.4 Dart/3.4.2 android/34
powersync-dart/1.6.4 Dart (flutter-web) Chrome/128 android
powersync-js/1.16.2 powersync-react-native/1.11.0 react-native/0.78 android/34
powersync-js/1.16.2 powersync-web/1.6.0 Chrome/128 android

Proof of success:

Screenshots