at-spi2-core: wrap at-spi-bus-launcher

Currently the following warnings and errors are logged on GNOME startup:

	Aug 22 19:34:16 kaiser dbus-daemon[1229]: [session uid=132 pid=1229] Activating via systemd: service name='org.a11y.Bus' unit='at-spi-dbus-bus.service' requested by ':1.8' (uid=132 pid=1246 comm="/nix/store/5anz
	kdq6src76c4lm4m98w2a8f3j2cc4-gnome-" label="kernel")
	Aug 22 19:34:16 kaiser systemd[1223]: Starting Accessibility services bus...
	Aug 22 19:34:16 kaiser at-spi-bus-laun[1341]: Using the 'memory' GSettings backend.  Your settings will not be saved or shared with other applications.
	Aug 22 19:34:16 kaiser dbus-daemon[1229]: [session uid=132 pid=1229] Successfully activated service 'org.a11y.Bus'
	Aug 22 19:34:16 kaiser systemd[1223]: Started Accessibility services bus.
	Aug 22 19:34:16 kaiser at-spi-bus-launcher[1341]: dbus-daemon[1345]: Activating service name='org.a11y.atspi.Registry' requested by ':1.0' (uid=132 pid=1246 comm="/nix/store/5anzkdq6src76c4lm4m98w2a8f3j2cc4-gnom
	e-" label="kernel")
	Aug 22 19:34:16 kaiser at-spi-bus-launcher[1341]: dbus-daemon[1345]: Successfully activated service 'org.a11y.atspi.Registry'
	Aug 22 19:34:16 kaiser at-spi-bus-launcher[1341]: SpiRegistry daemon is running with well-known name - org.a11y.atspi.Registry
	[…]
	Aug 22 19:34:26 kaiser dbus-daemon[1775]: [session uid=1000 pid=1775] Activating via systemd: service name='org.a11y.Bus' unit='at-spi-dbus-bus.service' requested by ':1.10' (uid=1000 pid=1852 comm="/nix/store/0k7r7imgs4zw3c9csldq7clmcyn4cy6k-gnome-" label="kernel")
	Aug 22 19:34:26 kaiser systemd[1769]: Starting Accessibility services bus...
	Aug 22 19:34:26 kaiser at-spi-bus-laun[1858]: g_settings_schema_source_lookup: assertion 'source != NULL' failed
	Aug 22 19:34:26 kaiser at-spi-bus-laun[1858]: g_settings_schema_source_lookup: assertion 'source != NULL' failed
	Aug 22 19:34:26 kaiser dbus-daemon[1775]: [session uid=1000 pid=1775] Successfully activated service 'org.a11y.Bus'
	Aug 22 19:34:26 kaiser systemd[1769]: Started Accessibility services bus.
	Aug 22 19:34:26 kaiser at-spi-bus-launcher[1858]: dbus-daemon[1862]: Activating service name='org.a11y.atspi.Registry' requested by ':1.0' (uid=1000 pid=1852 comm="/nix/store/0k7r7imgs4zw3c9csldq7clmcyn4cy6k-gnome-" label="kernel")
	Aug 22 19:34:26 kaiser at-spi-bus-launcher[1858]: dbus-daemon[1862]: Successfully activated service 'org.a11y.atspi.Registry'
	Aug 22 19:34:26 kaiser at-spi-bus-launcher[1858]: SpiRegistry daemon is running with well-known name - org.a11y.atspi.Registry

This patch starts wrapping the binary, fixing one of the stragglers from https://github.com/NixOS/nixpkgs/issues/14120.

Unfortunately, we could not use wrapGAppsHook due to dependency cycle.