Remove "line" geometry from lift gate (#679)

Lift gates should only be nodes ([wiki](see https://wiki.openstreetmap.org/w/index.php?title=Tag:barrier%3Dlift_gate&oldid=2406647)). This line probably is the cause of a validation issue, where ID suggests converting an orphaned lift_gate node into a way instead of suggesting it to be added as a node to a way.

Author: Discostu36

data/presets/barrier/lift_gate.json

@@ -10,8 +10,7 @@
         "opening_hours/covid19"
     ],
     "geometry": [
-        "vertex",
-        "line"
+        "vertex"
     ],
     "tags": {
         "barrier": "lift_gate"