Fix PHP 8 warnings

[Sama34]

I'm unsure about your approach at fixing these, I tried to keep compatibility with early 1.8 versions.

[SvePu]

Nice work! ... but there is a little mistake in pr =>

MyBB-Google-SEO/inc/plugins/google_seo/plugin.php

Line 214 in 08e6d0d

if($settings['google_seo_url_translate'] &&

[mboisde]

An additional line need to be fixed to work with php 8:

Replace (line ~624):
$GLOBALS['google_seo_portal_query'] &= $query;
by:
$GLOBALS['google_seo_portal_query'] =& $query;