www/qt5-webchannel: unbreak after 020693c166d1

Project MESSAGE: perl -w /usr/local/lib/qt5/bin/syncqt.pl -module QtWebChannel -version 5.15.8 -outdir /wrkdirs/usr/ports/www/qt5-webchannel/work/kde-qtwebchannel-5.15.8p3 -builddir /wrkdirs/usr/ports/www/qt5-webchannel/work/kde-qtwebchannel-5.15.8p3 /wrkdirs/usr/ports/www/qt5-webchannel/work/kde-qtwebchannel-5.15.8p3
sh: perl: not found

PR: 266007
Reported by: antoine (via exp-run)