Merge branch 'MDL-50313-28-featureidnumber' of git://github.com/mudrd8mz/moodle into MOODLE_28_STABLE

The constant is used by course/moodleform_mod.php to decide whether the
field 'ID number' (cmidnumber) should be included in the common module
settings section of the activity settings form. Activity modules that do
not use grades (such as the Label) can explicitly return false when
checking for this feature support. By default, all activity modules are
supposed to support it.

Otherwise the new capability risk does not get loaded

contains might select wrong activity
so using strict activity text checking

Backport of MDL-25721.

Thanks to Nadav Kavalerchik for the suggestion on patch

When additional names are disabled, they are no longer shown as
sortable headings in the enrolment and admin user tables.