feat(NpcBots/bot_ai): Change ranged bots to run to a tank or to their master when they have aggro

[atrapalis]

Changes Proposed:

This commit improves positioning for ranged bots which have aggro from the player's target. Previously bots would always keep a distance from their master which means they were effectively running away. With the changes proposed here, ranged bots will run to their master or to a bot tank/offtank when they get aggro - which is what you would expect a player to do. This will only be triggered if the player is targeting the creature which is attacking the ranged bot.

Overall this should improve crowd-control in dungeons and raids.

This PR proposes changes to:

• Core (units, players, creatures, game systems).
• Scripts (bosses, spell scripts, creature scripts).
• Database (SAI, creatures, etc).

Tests Performed:

This PR has been:

• Tested in-game by the author.
• Tested in-game by other community members/someone else other than the author/has been live on production servers.
• This pull request requires further testing and may have edge cases to be tested.

How to Test the Changes:

• This pull request can be tested by following the reproduction steps provided in the linked issue
• This pull request requires further testing. Provide steps to test your changes. If it requires any specific setup e.g multiple players please specify it as well.

1. Summon a ranged bot (and optionally a tank bot).
2. Body pull at least two creatures.
3. Allow the ranged bot to get aggro from one of the two creatures (e.g. by healing or attacking).
4. Target the creature which is now attacking the ranged bot. The ranged bot should move to the player, or to the tank bot if it was summoned in step 1.

Known Issues and TODO List:

• Do we need to consider impact for PvP gameplay? Perhaps this bot tactic would be counter-productive in PvP.

[trickerer]

The location for this code is right but could you please try to make bot move towards the selected target (ideally slightly past their front) instead of onto it?

P.S.

Man this AC PR template is kinda excessive for the bots huh

[atrapalis]

@trickerer That's a good point, I addressed this in 35130d5 just now. I set the radius to be 1.5 and randomised whether the bot should stop past or before the target - it should be well within melee range in either case.

[trickerer]

IsOffTank() check is redundant here, off-tank bot automatically has tanking role enabled