[bug] remove TF multiprocessing workers

[felixdittrich92]

This PR:

• Remove garbage TF workers -> crashes on GPU

@odulcy-mindee as discussed ^^

Any feedback is welcome :hugs:

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 96.37%. Comparing base (5eda559) to head (51be423).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #1635 +/- ## ========================================== - Coverage 96.39% 96.37% -0.03% ========================================== Files 164 164 Lines 7716 7715 -1 ========================================== - Hits 7438 7435 -3 - Misses 278 280 +2 ``` | [Flag](https://app.codecov.io/gh/mindee/doctr/pull/1635/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=mindee) | Coverage Δ | | |---|---|---| | [unittests](https://app.codecov.io/gh/mindee/doctr/pull/1635/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=mindee) | `96.37% <100.00%> (-0.03%)` | :arrow_down: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=mindee#carryforward-flags-in-the-pull-request-comment) to find out more.

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[felixT2K]

Thank you @felixdittrich92 ! Hopefully, TF will work as expected

Yeah that's not optimal (for training) but for the moment better as crashing all the time ^^