accessibility/at-spi2-core: update to 2.48.0

What's new in at-spi2-core 2.48.0:

* Add a "atk-only" build option. This allows atk to be built without libdbus
  installed, but it does not build libatspi or the atk bridge.
* Fix some typos in the documentation.

The atk-only support was added upstraem by Corey Halpin

Reported by:	Dmitry Pryakhin <graahnul.grom@ya.ru>
PR:		269996
Exp-run by:	antoine