Forward data to upload

tp-dropzone.js

@@ -82,16 +82,15 @@ class TpDropzone extends upload(dropzoneMixin(LitElement)) {
     }
   }
 
-  async upload() {
+  async upload(data = null) {
     if (this.file) {
-      const params = { url: this.url, data: null };
       document.dispatchEvent(new CustomEvent('before-upload', { 
-        detail: params, 
+        detail: { url: this.url, data }, 
         bubbles: true, 
         composed: true 
       }));
       
-      await this.uploadFiles(params.url, [this.file], params.data);
+      await this.uploadFiles(this.url, [this.file], data);
       
       // Clear file after successful upload
       this.file = null;