API review feedback changes

Made the follwing changes based on API council review
feedback

1. Made the class and its Builder class final
2. Removed methods that should not be in the builder
3. Changed the return type of available services
   from array to list.

Test: Unit tests
Bug 127657991

Change-Id: I3c2d406fed3ddaf62dee193c7657caf8c5bc13d2