[Albert] Add position ids to allowed uninitialized weights
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Fixes #6700 

# [Codecov](https://codecov.io/gh/huggingface/transformers/pull/6719?src=pr&el=h1) Report
> Merging [#6719](https://codecov.io/gh/huggingface/transformers/pull/6719?src=pr&el=desc) into [master](https://codecov.io/gh/huggingface/transformers/commit/625318f52516b413126be1bb1cb6818231d2eca6?el=desc) will **decrease** coverage by `0.00%`.
> The diff coverage is `100.00%`.

[![Impacted file tree graph](https://codecov.io/gh/huggingface/transformers/pull/6719/graphs/tree.svg?width=650&height=150&src=pr&token=9qOlN6Hb1c)](https://codecov.io/gh/huggingface/transformers/pull/6719?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master    #6719      +/-   ##
==========================================
- Coverage   79.49%   79.48%   -0.01%     
==========================================
  Files         156      156              
  Lines       28405    28406       +1     
==========================================
- Hits        22581    22579       -2     
- Misses       5824     5827       +3     
```


| [Impacted Files](https://codecov.io/gh/huggingface/transformers/pull/6719?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [src/transformers/modeling\_albert.py](https://codecov.io/gh/huggingface/transformers/pull/6719/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9tb2RlbGluZ19hbGJlcnQucHk=) | `83.53% <100.00%> (+0.03%)` | :arrow_up: |
| [src/transformers/generation\_tf\_utils.py](https://codecov.io/gh/huggingface/transformers/pull/6719/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9nZW5lcmF0aW9uX3RmX3V0aWxzLnB5) | `85.71% <0.00%> (-0.76%)` | :arrow_down: |

------

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> `Δ = absolute <relative> (impact)`, `ø = not affected`, `? = missing data`
> Powered by [Codecov](https://codecov.io/gh/huggingface/transformers/pull/6719?src=pr&el=footer). Last update [625318f...8f67175](https://codecov.io/gh/huggingface/transformers/pull/6719?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
