R1:55b44f53f87f

Fix possible recursive embeds in Dashboard text panels

Summary:
We currently detect tab panels embedding themselves, but do not detect text panels embedding themselves with `{Wxx}`.

Detect these self-embedding panels.

I had to add a bit of a hack to pass the parent panel PHIDs to the rule. Generally, I got the Markup API kind of wrong and want to update it, I'll file a followup with details about how I'd like to move forward.

Test Plan:
Created a text panel embedding itself, a tab panel embedding a…