[BUG][SHITHRI] Shithri-Neera unjoin-rejoing may cause a loop

[Udiknedormin]

Detected issues:

• If you un-join Shithri or Neera in another location, the other will go to their respective place of meeting instantly; I can see no way to implement "go to the same location as" though. It may be considered a corner-case though, as un-joining while in another location is generally pretty hacky and can be used to separate pairs in BG-I too.
• Unjoining Shithri without talking to her (and then leaving the location) may lead to a loop in which Neera is unjoined, tries to talk with Player1 and if Player1 agrees to her re-joining, she's un-joined again. The loop may be broken by rejoining them in an appropriate order.

Suggested solutions:

• "we" dialogues for both Shithri and Neera, that would override their basic ones; such a dialogue would always move both of them to the same location (probably Neera's, as it's more personal). It would have the same issues as similar dialogues in BG-I, but would work fine otherwise.