Revert pull request 3271 - wrapper to use hugging face algorithms for vocabulary building

[arunppsg]

Pull Request Template

Description

I would like to revert the pull request #3271 because for some reason, the unit test CI is failing randomly with a message no space left in the device during installation of dependency. For example, this is a unit test CI where the tests ran and this is a case where it failed.

Since it is causing a failure in installation, the new changes will also block other pull requests. Hence, reverting it will fix the issue temporarily by unblocking other pull requests.

Type of change

Please check the option that is related to your PR.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
  • In this case, we recommend to discuss your modification on GitHub issues before creating the PR
• Documentations (modification for documents)

Checklist

• My code follows the style guidelines of this project
  • Run yapf -i <modified file> and check no errors (yapf version must be 0.32.0)
  • Run mypy -p deepchem and check no errors
  • Run flake8 <modified file> --count and check no errors
  • Run python -m doctest <modified file> and check no errors
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• New unit tests pass locally with my changes
• I have checked my code and corrected any misspellings

[rbharath]

LGTM, feel free to merge in once ready