revert: remove setting color in highlight substructure

src/component/component.js

@@ -118,13 +118,12 @@ class pdbLigandEnv extends LitElement {
   //   this.display.showWeights(contactType);
   // }
 
-  set highlightSubstructure(substructure, color) {
+  set highlightSubstructure(substructure) {
     if (!this.display) {
       return;
     }
     this.substructureHighlight = substructure;
-    this.highlightColor = color;
-    this.display.addLigandHighlight(this.substructureHighlight, this.highlightColor);
+    this.display.addLigandHighlight(this.substructureHighlight);
     
   }