Change PHP default version to 8.0

• databases/xapian-bindings is a mata port which do not have php:flavors and is unable to be MARKED to IGNORE as one of it's dependent databases/php-xapian do not support php8.0. Hence this creates a circular dependency and it fails to start bulk building. So for now remove PHP from OPTIONS_DEFAULT.

PR: 260595
Approved by: ale portmgr(exp-run)
Sponsored by: Bounce Experts