Remove dialogFitWindow and jquery.ui.dialog from mwEmbedUtil

* jquery.mwEmbedUtil is a startup module, which means it loads early
  on every page
* This brought in jquery.ui.dialog.  However, it was only actually
  used in dialogFitWindow.  In turn, I can't find anywhere that's used
  in TimedMediaHandler or here.

Bug: 55550
Change-Id: I2c5318e7127ee2d410e27f542472b33faa56cd98
Merge "Remove dialogFitWindow and jquery.ui.dialog from mwEmbedUtil"