[sysprof] libsysprof-ui: remove EggThreeGrid from build

[Christian Hergert <chergert src gnome org>]

commit 3d02ea81fa32cd23bd53c1e834397e2deac84d89
Author: Christian Hergert <chergert redhat com>
Date:   Fri Jul 22 14:50:14 2022 -0700

    libsysprof-ui: remove EggThreeGrid from build

 src/libsysprof-ui/egg-three-grid.c | 781 -------------------------------------
 src/libsysprof-ui/egg-three-grid.h |  51 ---
 src/libsysprof-ui/meson.build      |   1 -
 3 files changed, 833 deletions(-)
---
diff --git a/src/libsysprof-ui/meson.build b/src/libsysprof-ui/meson.build
index d87a093d..f2fbfa93 100644
--- a/src/libsysprof-ui/meson.build
+++ b/src/libsysprof-ui/meson.build
@@ -14,7 +14,6 @@ libsysprof_ui_private_sources = [
   'egg-handle.c',
   'egg-paned.c',
   'egg-resizer.c',
-  'egg-three-grid.c',
 
   'pointcache.c',
   'rectangles.c',