Popup does not close after attaching merge request attachment

The following discussion from !7 (merged) should be addressed:

• @ClemMakesApps started a discussion:

  Making a note here that for some reason, this isn't working as it should be. Popup does not close even though it is called and no errors are created in the console

changed title from Follow-up from "Add ability to attach merge request" to Popup does not close after attaching merge request attachment

mentioned in merge request !12 (merged)

After some further investigation, it looks like the callback needs to be the one to pass the t (trelloObject) to the callback in order for t.close() to work. I was previously passing in t from the parent context so that I could keep the parameter order with t as the first parameter.

changed milestone to %1.0