refactor: Specified imports of file_utils in __init__.py

[zalakbhalani]

Fixed error while importing functions like is_tf_available and is_torch_available because it is in file_utils.py file.

[fg-mindee]

Hi @zalakbhalani 👋

Thanks for the PR!
While it's true that those functions are located in doctr/file_utils.py, we took some precaution to include this in the high-level __init__.py (cf. https://github.com/mindee/doctr/blob/main/doctr/__init__.py#L1)

As you can see, without any modification of the codebase, the following snippet does work:

from doctr import is_tf_available, is_torch_available

If you manage to run the snippet, I'm not sure this PR is a "fix" as stated in the title 😅 If not, could you open an issue showing the error that you got?

[zalakbhalani]

Oh ok. Thanks for the update. I faced this issue when I used doctr v0.2.1. I forgot to upgrade to newer versions. It is not a fix but can you approve the PR for the readability because at doctr/models/backbones/mobilenet/init.py you used from doctr.file_utils import is_tf_available, is_torch_available this confuses me.

[codecov]

Codecov Report

Merging #447 (171c0ff) into main (369a787) will increase coverage by 0.02%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main     #447      +/-   ##
==========================================
+ Coverage   95.84%   95.87%   +0.02%     
==========================================
  Files          96       96              
  Lines        3997     3997              
==========================================
+ Hits         3831     3832       +1     
+ Misses        166      165       -1     

Flag	Coverage Δ
unittests	95.87% <100.00%> (+0.02%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
doctr/models/backbones/resnet/__init__.py	100.00% <100.00%> (ø)
doctr/models/backbones/vgg/__init__.py	100.00% <100.00%> (ø)
doctr/models/recognition/sar/__init__.py	100.00% <100.00%> (ø)
...dels/detection/differentiable_binarization/base.py	91.97% <0.00%> (+0.61%)	⬆️

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[fg-mindee]

Thanks for the PR!

[zalakbhalani]

Thank you