Delete deprecated TrainerLoggingMixin

[carmocca]

What does this PR do?

See title

Does your PR introduce any breaking changes? If yes, please list them.

Removes deprecated code

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[codecov]

Codecov Report

Merging #8609 (ab18964) into master (8c27fa7) will decrease coverage by 0%.
The diff coverage is n/a.

@@          Coverage Diff           @@
##           master   #8609   +/-   ##
======================================
- Coverage      93%     93%   -0%     
======================================
  Files         169     168    -1     
  Lines       13959   13951    -8     
======================================
- Hits        12917   12909    -8     
  Misses       1042    1042