refactor(character): Use tutorial natives instead of manual bucket setting

[solareon]

Description

Routing buckets may overlap. The natives do a better job of hiding the characters. This is similar to #473 but moves the tutorial end to the QBCore:Client:OnPlayerLoaded event to end the tutorial session with the appropriate native.

Additionally it only calls the tutorial session start one time if somehow the choosecharacter() function got called twice without being disabled cause who knows if that works right.

NOTE: I have NOT tested this. Do not merge without extensive testing in a multiplayer environment.

Checklist

• I have personally loaded this code into an updated Qbox project and checked all of its functionality.
• My pull request fits the contribution guidelines & code conventions.