Move filename input logic to its own function

src/main/resources/static/js/multitool/PdfContainer.js

@@ -74,6 +74,16 @@ class PdfContainer {
         input.onchange = async(e) => {
             const files = e.target.files;
             if (files.length > 0) {
+                updateFilenameInput()
+            }
+
+            this.addPdfsFromFiles(files, nextSiblingElement);
+        }
+
+        input.click();
+    }
+
+    updateFilenameInput() {
         const filenameInput = document.getElementById('filename-input');
         const pagesContainer = document.getElementById('pages-container');
         const downloadBtn = document.getElementById('export-button');
@@ -93,13 +103,6 @@ class PdfContainer {
         } else {
             filenameInput.value = this.filename;
         }
-
-            }
-
-            this.addPdfsFromFiles(files, nextSiblingElement);
-        }
-
-        input.click();
     }
 
     async addPdfsFromFiles(files, nextSiblingElement) {