graphics/pecl-imagick: Update/bump consumers

www/nextcloud, www/piwigo and www/wordpress had some custom logic to
select the pecl-imagick port based on the default ImageMagick version.
This is now obsolete with the removal of pecl-imagick-im7 and must be
removed. As this changes dependencies, also bump PORTREVISION in these
ports.

Other consumers of pecl-imagick don't need a bump because they only use
ImageMagick through the PHP API, they don't directly link any shared
libs.

PR:		268833
Approved by:	portmgr (blanket)