fix: keep plugin_paths while removing jitsi-meet-tokens (#7632)

debian/jitsi-meet-tokens.postrm

             APP_SECRET=$RET
 
             # Revert prosody config
-            sed -i 's/plugin_paths/--plugin_paths/g' $PROSODY_HOST_CONFIG
             sed -i 's/authentication = "token"/authentication = "anonymous"/g' $PROSODY_HOST_CONFIG
             sed -i "s/ app_id=\"$APP_ID\"/ --app_id=\"example_app_id\"/g" $PROSODY_HOST_CONFIG
             sed -i "s/ app_secret=\"$APP_SECRET\"/ --app_secret=\"example_app_secret\"/g" $PROSODY_HOST_CONFIG