Remove useless if statement on WFS writeGetFeature

Remove the if(options) {} statement as the options is not optional and
the further code expect to have this parameter.

src/ol/format/WFS.js

@@ -473,7 +473,6 @@ class WFS extends XMLFeature {
     node.setAttribute('service', 'WFS');
     node.setAttribute('version', this.version_);
     let filter;
-    if (options) {
     if (options.handle) {
       node.setAttribute('handle', options.handle);
     }
@@ -510,7 +509,6 @@ class WFS extends XMLFeature {
         filter = bbox;
       }
     }
-    }
     node.setAttributeNS(
       XML_SCHEMA_INSTANCE_URI,
       'xsi:schemaLocation',