[vega] fix vega map validation errors crashing vega (#112700)

* [vega] fix vega map validation errors crashing vega

* eslint

Co-authored-by: Kibana Machine <42973632+kibanamachine@users.noreply.github.com>

src/plugins/vis_types/vega/public/vega_view/vega_map_view/view.ts

@@ -72,7 +72,7 @@ export class VegaMapView extends VegaBaseView {
     const { zoom, maxZoom, minZoom } = validateZoomSettings(
       this._parser.mapConfig,
       defaults,
-      this.onWarn
+      this.onWarn.bind(this)
     );
     const { signals } = this._vegaStateRestorer.restore() || {};