Fix disabling button during file upload

This is to fix an issue that is causing a 500 error when submitting the
Tpic form before a file upload has fully completed. The lines that were
restoring the button state were outside of the promise, so they re-activated
the button too early.

Author: Oli0li

app/javascript/controllers/upload_controller.js

@@ -42,10 +42,10 @@ export default class extends Controller {
           this.filesContainerTarget.innerHTML += data.html;
           filesInput.value = "";
         }
-      });
 
-    this.submitButtonTarget.classList.remove("disabled");
-    this.spinnerTarget.classList.add("d-none");
+        this.submitButtonTarget.classList.remove("disabled");
+        this.spinnerTarget.classList.add("d-none");
+      });
   }
 
   removeFile(event) {