x11-toolkits/gstreamer1-plugins-gtk4: remove port after 88a566688d92

Avoid being a burden for multimedia@ due to unmerged patch upstream.
If re-added, please, change maintainer and use the same style as gtk3
plugin i.e., x11-toolkits/gstreamer1-plugins-gtk

This reverts commit d88adb1c0af3a6b9160a0ecdcc242ad91973d6dd.