Simplify the PDFDocumentProperties.#updateUI method

We can remove the `reset`-parameter, since it's redundant, given that it's only used after `PDFDocumentProperties.#reset` has been invoked which means that `this.#fieldData === null` which is equivalent to resetting.
Also, we don't need to have two separate loops in order to update the UI in this method.

web/pdf_document_properties.js

@@ -192,7 +192,7 @@ class PDFDocumentProperties {
   setDocument(pdfDocument) {
     if (this.pdfDocument) {
       this.#reset();
-      this.#updateUI(true);
+      this.#updateUI();
     }
     if (!pdfDocument) {
       return;
@@ -216,20 +216,15 @@ class PDFDocumentProperties {
    * NOTE: If the contents of a particular field is neither a non-empty string,
    *       nor a number, it will fall back to `DEFAULT_FIELD_CONTENT`.
    */
-  #updateUI(reset = false) {
-    if (reset || !this.#fieldData) {
-      for (const id in this.fields) {
-        this.fields[id].textContent = DEFAULT_FIELD_CONTENT;
-      }
-      return;
-    }
-    if (this.overlayManager.active !== this.dialog) {
+  #updateUI() {
+    if (this.#fieldData && this.overlayManager.active !== this.dialog) {
       // Don't bother updating the dialog if has already been closed,
+      // unless it's being reset (i.e. `this.#fieldData === null`),
       // since it will be updated the next time `this.open` is called.
       return;
     }
     for (const id in this.fields) {
-      const content = this.#fieldData[id];
+      const content = this.#fieldData?.[id];
       this.fields[id].textContent =
         content || content === 0 ? content : DEFAULT_FIELD_CONTENT;
     }