gnu: at-spi2-core-minimal: Update to 2.45.90, rename to at-spi2-core.

at-spi2-core now includes at-spi2-atk (see:
https://gitlab.gnome.org/GNOME/at-spi2-core/-/merge_requests/78).

* gnu/packages/gtk.scm (at-spi2-core-minimal): Rename to...
(at-spi2-core): ... this.  Update to 2.45.90.
[phases]{check}: Adjust per upstream changes.
[inputs]: Add libxml2.
[native-inputs]: Delete labels.  Add gsettings-desktop-schemas,
python-dbusmock and python-pytest.
(at-spi2-core-with-documentation): Variable renamed from at-spi2-core.  Adjust
accordingly to changes to parent (inherited) package, and use gexps.
(at-spi2-atk): Deprecate by at-spi2-core.
(gtk+)[propagated-inputs]: Use at-spi2-core.
* gnu/packages/gnome.scm (orca)[inputs]: Likewise.
* gnu/packages/gnome.scm (gnome): Likewise.

gnu/packages/chromium.scm

@@ -878,7 +878,7 @@
     (inputs
      (list alsa-lib
            atk
-           at-spi2-atk
+           at-spi2-core
            cups
            curl
            dbus