Reintroduce clean_text on BertTokenizer call which was removed by mistake in #4723
Signed-off-by: Morgan Funtowicz <funtowiczmo@gmail.com>

closes #7665 
# [Codecov](https://codecov.io/gh/huggingface/transformers/pull/5749?src=pr&el=h1) Report
> Merging [#5749](https://codecov.io/gh/huggingface/transformers/pull/5749?src=pr&el=desc) into [master](https://codecov.io/gh/huggingface/transformers/commit/5668fdb09e1bcd888930c1ff242bf200649da39c?el=desc) will **increase** coverage by `2.02%`.
> The diff coverage is `100.00%`.

[![Impacted file tree graph](https://codecov.io/gh/huggingface/transformers/pull/5749/graphs/tree.svg?width=650&height=150&src=pr&token=9qOlN6Hb1c)](https://codecov.io/gh/huggingface/transformers/pull/5749?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master    #5749      +/-   ##
==========================================
+ Coverage   75.33%   77.36%   +2.02%     
==========================================
  Files         195      146      -49     
  Lines       39826    26048   -13778     
==========================================
- Hits        30003    20151    -9852     
+ Misses       9823     5897    -3926     
```


| [Impacted Files](https://codecov.io/gh/huggingface/transformers/pull/5749?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [src/transformers/tokenization\_bert.py](https://codecov.io/gh/huggingface/transformers/pull/5749/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy90b2tlbml6YXRpb25fYmVydC5weQ==) | `95.00% <100.00%> (+2.96%)` | :arrow_up: |
| [src/transformers/commands/env.py](https://codecov.io/gh/huggingface/transformers/pull/5749/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9jb21tYW5kcy9lbnYucHk=) | `0.00% <0.00%> (-100.00%)` | :arrow_down: |
| [src/transformers/commands/\_\_init\_\_.py](https://codecov.io/gh/huggingface/transformers/pull/5749/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9jb21tYW5kcy9fX2luaXRfXy5weQ==) | `0.00% <0.00%> (-100.00%)` | :arrow_down: |
| [src/transformers/commands/transformers\_cli.py](https://codecov.io/gh/huggingface/transformers/pull/5749/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9jb21tYW5kcy90cmFuc2Zvcm1lcnNfY2xpLnB5) | `0.00% <0.00%> (-87.50%)` | :arrow_down: |
| [src/transformers/modeling\_tf\_mobilebert.py](https://codecov.io/gh/huggingface/transformers/pull/5749/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9tb2RlbGluZ190Zl9tb2JpbGViZXJ0LnB5) | `23.38% <0.00%> (-73.56%)` | :arrow_down: |
| [src/transformers/commands/download.py](https://codecov.io/gh/huggingface/transformers/pull/5749/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9jb21tYW5kcy9kb3dubG9hZC5weQ==) | `0.00% <0.00%> (-65.00%)` | :arrow_down: |
| [src/transformers/modeling\_tf\_flaubert.py](https://codecov.io/gh/huggingface/transformers/pull/5749/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9tb2RlbGluZ190Zl9mbGF1YmVydC5weQ==) | `25.82% <0.00%> (-63.85%)` | :arrow_down: |
| [src/transformers/commands/serving.py](https://codecov.io/gh/huggingface/transformers/pull/5749/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9jb21tYW5kcy9zZXJ2aW5nLnB5) | `0.00% <0.00%> (-55.89%)` | :arrow_down: |
| [src/transformers/commands/run.py](https://codecov.io/gh/huggingface/transformers/pull/5749/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9jb21tYW5kcy9ydW4ucHk=) | `0.00% <0.00%> (-53.34%)` | :arrow_down: |
| [src/transformers/tokenization\_camembert.py](https://codecov.io/gh/huggingface/transformers/pull/5749/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy90b2tlbml6YXRpb25fY2FtZW1iZXJ0LnB5) | `37.03% <0.00%> (-53.13%)` | :arrow_down: |
| ... and [185 more](https://codecov.io/gh/huggingface/transformers/pull/5749/diff?src=pr&el=tree-more) | |

------

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> Powered by [Codecov](https://codecov.io/gh/huggingface/transformers/pull/5749?src=pr&el=footer). Last update [5668fdb...25ff60c](https://codecov.io/gh/huggingface/transformers/pull/5749?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
<|||||>Do we have unit tests for that `clean_text` functionality 🤔<|||||>@stefan-it I'll add one, had to switch to something else in-between <|||||>Do you mind making the code quality and the tests pass before we merge?<|||||>This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.
