Apply suggestions from code review

Co-authored-by: Thomas Gran <[email protected]>

Author: leonardehrenfried

src/main/java/org/opentripplanner/model/fare/FareProduct.java

@@ -48,15 +48,9 @@ public String toString() {
       .of(FareProduct.class)
       .addStr("id", id.toString())
       .addObj("amount", amount);
-    if (duration != null) {
-      builder.addDuration("duration", duration);
-    }
-    if (category != null) {
-      builder.addObj("category", category);
-    }
-    if (medium != null) {
-      builder.addObj("medium", medium);
-    }
+    builder.addDuration("duration", duration);
+    builder.addObj("category", category);
+    builder.addObj("medium", medium);
 
     return builder.toString();
   }

src/main/java/org/opentripplanner/model/plan/UnknownTransitPathLeg.java

@@ -85,11 +85,7 @@ public int getGeneralizedCost() {
 
   @Override
   public void setFareProducts(List<FareProductUse> products) {
-    throw new UnsupportedOperationException(
-      "Setting the fare products on a leg of type %s is unsupported.".formatted(
-          this.getClass().getSimpleName()
-        )
-    );
+    throw new UnsupportedOperationException();
   }
 
   @Override