fix: add tracking mode conversion in onCameraTrackingChanged

[XanderD99]

fix for #375

just a fast fix to map the mode to the flutter enum values.

[m0nac0]

Thanks for contributing, and sorry you had to wait for feedback on this!
Do you know if iOS works fine? Looking at the docs at https://maplibre.org/maplibre-native/ios/api/Enums/MGLUserTrackingMode.html#/MGLUserTrackingMode it seems that the iOS and Flutter constant values for the enums should be the same, but it would be good to know should you have already testet it (no worries if you don't know).

[XanderD99]

Yeah iOS seems to be working fine they use basically the same types like the flutter package. Android does like you said use different types and enum values