fix: remove redundant w:pic "insertion"

The removed `._insert_pic(pic)` call is redundant because the `pic`
element is already inserted by the prior `CT_Inline.new()` call. The
reason the second `._insert_pic()` call did not add a second `pic`
element is that the `pic` element is the same instance in both cases. So
that `pic` element is "moved" from where it was, back to the same place.

Author: scanny

src/docx/oxml/shape.py

@@ -100,7 +100,6 @@ def new_pic_inline(
         pic_id = 0  # Word doesn't seem to use this, but does not omit it
         pic = CT_Picture.new(pic_id, filename, rId, cx, cy)
         inline = cls.new(cx, cy, shape_id, pic)
-        inline.graphic.graphicData._insert_pic(pic)
         return inline
 
     @classmethod