Fixing tokenizer when `transformers` is installed without `tokenizers` (#26236)

* Fixing tokenizer when tokenizers is not installed

* Adding __repr__ function and repr=True in dataclass

* Revert "Adding __repr__ function and repr=True in dataclass"

This reverts commit 18839505d1cada3170ed623744d3e75008a18bdc.

src/transformers/tokenization_utils_base.py

@@ -101,6 +101,9 @@ else:
         def __getstate__(self):
             return self.__dict__
 
+        def __str__(self):
+            return self.content
+
     @dataclass
     class EncodingFast:
         """This is dummy class because without the `tokenizers` library we don't have these objects anyway"""