multimedia/gstreamer1-plugins: Fix build in the presence of tremor

Details:
If audio/libtremor is installed, the dependency may be picked up by the
auto detection. This leads so a build error in gstreamer1-plugins-ogg.
This patch explicitly disables tremor in gstreamer-* ports.

PR: 268560
Reported by: gja822@narod.ru
MFH: 2023Q1