osm_to_railjson: don't parse unecessary signals

Don't parse signals when we generate them, as they will be overridden anyway.

Signed-off-by: Simon <sim.gaubert.sg@gmail.com>

Author: SaumonDesMers

editoast/osm_to_railjson/src/osm_to_railjson.rs

@@ -71,7 +71,11 @@ pub fn parse_osm(
     }
 
     let nodes_tracks = NodeToTrack::from_edges(&edges);
-    let signals = signals(&osm_pbf_in, &nodes_tracks, &adjacencies);
+    let signals = if generate_signals {
+        vec![]
+    } else {
+        signals(&osm_pbf_in, &nodes_tracks, &adjacencies)
+    };
     let mut railjson = RailJson {
         extended_switch_types: vec![],
         detectors: signals.iter().map(detector).collect(),