[Lua] Add ZNM NPC to unique_event

[hooksta4]

I affirm:

• I understand that if I do not agree to the following points by completing the checkboxes my PR will be ignored.
• I understand I should leave resolving conversations to the LandSandBoat team so that reviewers won't miss what was said.
• I have read and understood the Contributing Guide and the Code of Conduct.
• I have tested my code and the things my code has changed since the last commit in the PR and will test after any later commits.

What does this pull request do?

Place holder for ZNM NPC's Sanraku and Ryo in unique_event. Will determine which dialog players will get upon talking to either NPC.

Steps to test these changes

None at this time.

[zach2good]

These aren't fast-moving files, so why not just do the rest of the logic now too? Ekokoko is a full example of how this system works.

[hooksta4]

So I don't forget it.

[zach2good]

To clarify what I want from this PR: The latching logic for "I have spoken to Sanraku for the first time", and "I have spoken to Sanraku for subsequent times" - which is just a single if/else block if memory serves.

Using a single-line PR as a way for you not to forget that a feature exists is pointless.