Change computegles31 example to a manual test

Change-Id: I652daf3ccbb921c5eb73b48586ee9616c7704b97
Reviewed-by: Christian Strømme <christian.stromme@qt.io>
(cherry picked from commit 5a36f4cd9c6252b98786801f5a33962c1e5a1ca0)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

examples/opengl/CMakeLists.txt

@@ -13,6 +13,5 @@ if(TARGET Qt6::Widgets)
     qt_internal_add_example(cube)
     qt_internal_add_example(textures)
     qt_internal_add_example(hellogles3)
-    qt_internal_add_example(computegles31)
     qt_internal_add_example(stereoqopenglwidget)
 endif()

examples/opengl/opengl.pro

@@ -13,6 +13,5 @@ qtHaveModule(widgets) {
                cube \
                textures \
                hellogles3 \
-               computegles31 \
                stereoqopenglwidget
 }