This also removes the only occurrence of the
"com.sun.star.frame.ToolboxController" service. However it shouldn't
be considered as API CHANGE, as no 3rd-party code should rely on
undocumented services, and fortunately a toolbox controller like this
has no use for 3rd-party anyway.

BTW there are other cases of using non-existent (unique) service
names for toolbox controllers in non-sfx2 modules, rather than using
the standard "com.sun.star.frame.ToolbarController". There is
OToolboxController in reportdesign (which I hope to remove soon too,
as it's just a wrapper around SvxColorToolBoxControl). And there was
also ShapeToolbarController in chart2 which I removed in
2aea9e37 ("Introduce generic sub toolbar
controller").

Change-Id: Iea8858be2406f32bb5a022920b4b1cee70603c09