**Original issue:**
Bots/Characters received duplicate spells during randomization process.
**Root cause:**
When `PlayerbotFactory::Randomize` is processed, `InitSkills` is called
AFTER `InitAvailableSpells`, which causes the duplicate spells issue
because the skillline ability spell is already learned when processing
spells from trainers (`InitAvailableSpells`).
We simply need to change the order of the randomization process: skills
should be handled first, then spells. An alternative approach would be
to adjust the skillline abilities and check each spell for every skill,
but that seems redundant since we already have checks for the trainer's
spells.
`InitSkills` -> `SetRandomSkill` -> `SetSkill` ->
`learnSkillRewardedSpells` -> `learnSpell` -> duplicate error...
**Steps to reproduce:**
1. create common character and login with it
2. set level for this character eq. 80 (`.set level 79`)
3. create and run macro:
```
/g .playerbots bot initself
/g .saveall
```
4. logout -> login and run macro again
**Note:**
Also added checks for the trainer's spells since `GetSpell` can return
nullptr. Updated `LearnQuestSpells` after recent changes and used the
same logic and implementation from `Player::learnQuestRewardedSpells`.
Yes, we need to cast spells, or we should handle all spell effects that
quests/trainers have (for ex.: `SPELL_EFFECT_SKILL_STEP`,
`SPELL_EFFECT_UNLEARN_SPECIALIZATION`, `SPELL_EFFECT_BIND`).
