fix(components/validation): correct return type for static url valdation function when called with validation options (#809)

Author: Blackbaud-TrevorBurch

libs/components/validation/src/lib/modules/validators/validators.ts

@@ -41,7 +41,7 @@ export class SkyValidators {
    */
   public static url(
     skyUrlValidationOptions: SkyUrlValidationOptions
-  ): ValidatorFn | null;
+  ): ValidatorFn;
 
   public static url(
     value: AbstractControl | SkyUrlValidationOptions