get_magic_quotes_xxx functions removed in php80

The get_magic_quotes_gpc() and get_magic_quotes_runtime() functions were deprecated in php74 (always returning false).

In php80 they have been removed and now they throw an error.

This issue is about to review all existing cases, ensuring that:

• they are being executed conditionally [OR]
• if not conditionally, modify code to always consider the "false" value that they were returning in previous php versions.

List of files to inspect (also added the set, that was removed in php 5.x!):

$ ag '(set|get)_magic_quotes' -l

enrol/lti/ims-blti/OAuth.php

lib/tcpdf/include/tcpdf_static.php

lib/tcpdf/CHANGELOG.TXT

lib/pear/README_MOODLE.txt

lib/horde/framework/Horde/Util.php

lib/htmlpurifier/HTMLPurifier/Config.php

h5p/h5plib/v124/joubel/editor/ckeditor/samples/old/assets/posteddata.php