Stop autofilling default analysis gloss LT-15175

* Stops the Create method on LexEntry factory used by the
  InsertNewEntry dialog from always filling the default analysis
  language gloss with the text from the string of the first
  analysis language.
* Tests the new methods necessary for the change and the bug fix

Change-Id: Ib7aba6c761b43742b61076b80702b784fdf2d214