Action Invoker source/target doesn’t work with `wait` meta action

[BAndysc]

Describe the bug ActionInvoker is null after wait action.

Version (commit hash) d2ad04b3f53abf5738ab2e178f3a2796d52e66fe

To Reproduce Steps to reproduce the behaviour:

1. Create a script
2. Create any event which has „invoker”
3. Add action wait
4. Add any action with invoker source
5. Test in game - doesn’t work, because invoker is null there

Expected behaviour Action Invoker should work as expected after wait action.

Proposed solution Best option would be to change TC to pass invoker here https://github.com/TrinityCore/TrinityCore/blob/master/src/server/game/AI/SmartScripts/SmartScript.cpp#L1542

Another option would be to change invoker to storedTarget in the editor, but there is a risk, this storedTargetID will be taken already. We can inform user during exporting that some storedTarget will be reserved?