Expose AndroidPosition from geolocator

[LorenzSchueler]

Expose AndroidPosition directly from geolocator. This makes it no longer necessary to depend on geolocator_android directly when using AndroidPosition (similary to AndroidSettings).

Pre-launch Checklist

• [x] I made sure the project builds.
• [x] I read the Contributor Guide and followed the process outlined there for submitting PRs.
• [x] I updated pubspec.yaml with an appropriate new version according to the pub versioning philosophy, or this PR is does not need version changes.
• [x] I updated CHANGELOG.md to add a description of the change.
• [x] I updated/added relevant documentation (doc comments with ///).
• [x] I rebased onto main.
• [x] I added new tests to check the change I am making, or this PR does not need tests.
• [x] I made sure all existing and new tests are passing.
• [x] I ran dart format . and committed any changes.
• [x] I ran flutter analyze and fixed any errors.