fix: max file per upload not working with dynamic value

Author: gjulivan

packages/pluggableWidgets/file-uploader-web/src/stores/FileUploaderStore.ts

@@ -82,6 +82,7 @@ export class FileUploaderStore {
             errorMessage: observable,
             allowedFormatsDescription: computed,
             maxFilesPerUpload: computed,
+            _maxFilesPerUpload: observable,
             isFileUploadLimitReached: computed
         });