fix typo

Author: lohanidamodar

templates/dart/lib/src/input_file.dart.twig

@@ -9,7 +9,7 @@ class InputFile {
   @Deprecated('Use `InputFile.fromPath` or `InputFile.fromBytes` instead.')
   InputFile({this.path, this.filename, this.contentType, this.bytes}) {
     if (path == null && bytes == null) {
-      throw AppwriteException('One of `path` or `bytes`  is required');
+      throw {{ spec.title | caseUcfirst }}Exception('One of `path` or `bytes`  is required');
     }
   }