Merge branch 'install_39_STABLE' of https://git.in.moodle.com/amosbot/moodle-install into MOODLE_39_STABLE

Merge branch 'MDL-71060-39' of https://github.com/NashTechOpenUniversity/moodle into MOODLE_39_STABLE

Merge branch 'install_39_STABLE' of https://git.in.moodle.com/amosbot/moodle-install into MOODLE_39_STABLE

Without this, people can craft URLs that other users might use not realising
what they do - and as a XSS vulnerability, it could do any number of things the
clicking-user has access to do on the site.

Change-Id: I82adc71e8706d8929011b4b24523d5b62b8ccea1

Merge branch 'MDL-70049-39_count_submissions' of https://github.com/agrowe/moodle into MOODLE_39_STABLE

because of changes in PHP8 the '' == 0 is no longer true and the error in the google api wrapper was discovered

See also 643b0cca.

 * The button to "Add group/grouping access restriction" under
   common module settings should only be present if corresponding
   availability plugins are enabled; and
 * Prevent the same button behaving as a submit button, which
   intercepted the user hitting return in the form and added a
   restriction without deliberate action taken by the user.

On PHP7.4, trying to access array offsets of NULL triggers a notice.

In order to allow for correct seb:// or sebs:// calls without browser
warnings of insecure links, it is not possible to send a get request
with an attached cmid parameter to the unknown seb:// or sebs://
URL via a form button.
We've got to use a <a href> link outside a form to circumvent
browsers warning of an insecure link and call Safe Exam Browser
correctly.

Table names and database name now enclosed in backticks.
admin/cli/mysql_collation.php failed if $CFG->prefix was blank with
MySQL 8.0 because table 'groups' conflicted with a new reserved word.

Note that this quotes both mysql_collation.php and mysql_compressed_rows.php
but only the former was mal-functioning.

The case of mysql_compressed_rows.php is a little bit special because
not all tables are processed, only those having big rows. And the groups
table is not one of them. In any case, better add the quotes there for
any future case.

Also, when testing this patch https://tracker.moodle.org/browse/MDL-71512
was discovered and will need to be fixed to make core 100% compliant
with MySQL 8.0 and MariaDB 10.6 and up.