Bug 1658031, update print preview only for settings with flags to avoid a progress dialog r=mstriemer

Differential Revision: https://phabricator.services.mozilla.com/D86769

toolkit/components/printing/content/print.js

@@ -117,10 +117,9 @@ var PrintEventHandler = {
 
       if (flags) {
         PSSVC.savePrintSettingsToPrefs(this.settings, true, flags);
+        this.updatePrintPreview();
       }
 
-      this.updatePrintPreview();
-
       document.dispatchEvent(
         new CustomEvent("print-settings", {
           detail: this.viewSettings,