tracker-extract: Drop the correct midi plugin name from the GST registry
Commit 2425ed05 attempted to drop fluidsynth GStreamer plugin which tries to access hardware devices during metadata extraction and triggers the seccomp jail. However the wrong name was pulled here, we should use the name of the plugin itself, not the decoder element.
Fixes: 2425ed05 - tracker-extract: Avoid the fluiddec gstreamer plugin
Closes: #249 (closed)